diff --git a/schema/json/metaschema-datatypes.json b/schema/json/metaschema-datatypes.json
new file mode 100644
index 000000000..133f56eb0
--- /dev/null
+++ b/schema/json/metaschema-datatypes.json
@@ -0,0 +1,148 @@
+{
+  "$schema" : "http://json-schema.org/draft-07/schema#",
+  "$id" : "http://csrc.nist.gov/ns/oscal/1.0/metaschema-datatypes-schema.json",
+  "$comment" : "OSCAL Unified Model of Models",
+  "type" : "object",
+  "definitions" : {
+    "Base64Datatype": {
+      "description": "Binary data encoded using the Base 64 encoding algorithm as defined by RFC4648.",
+      "type": "string",
+      "pattern": "^[0-9A-Za-z+/]+={0,2}$",
+      "contentEncoding": "base64"
+    },
+    "BooleanDatatype": {
+      "description": "A binary value that is either: true or false.",
+      "type": "boolean"
+    },
+    "DateDatatype": {
+      "description": "A string representing a 24-hour period with an optional timezone.",
+      "type": "string",
+      "pattern": "^(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))(Z|[+-][0-9]{2}:[0-9]{2})?$"
+    },
+    "DateWithTimezoneDatatype": {
+      "description": "A string representing a 24-hour period with a required timezone.",
+      "type": "string",
+      "pattern": "^(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))(Z|[+-][0-9]{2}:[0-9]{2})$"
+    },
+    "DateTimeDatatype": {
+      "description": "A string representing a point in time with an optional timezone.",
+      "type": "string",
+      "pattern": "^(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])(\\.[0-9]*[1-9])?(Z|(-((0[0-9]|1[0-2]):00|0[39]:30)|\\+((0[0-9]|1[0-4]):00|(0[34569]|10):30|(0[58]|12):45)))?$"
+    },
+    "DateTimeWithTimezoneDatatype": {
+      "description": "A string representing a point in time with a required timezone.",
+      "type": "string",
+      "format": "date-time",
+      "pattern": "^(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])(\\.[0-9]*[1-9])?(Z|(-((0[0-9]|1[0-2]):00|0[39]:30)|\\+((0[0-9]|1[0-4]):00|(0[34569]|10):30|(0[58]|12):45)))$"
+    },
+    "DayTimeDurationDatatype": {
+      "description": "An amount of time quantified in days, hours, minutes, and seconds.",
+      "type": "string",
+      "format": "duration",
+      "pattern": "^-?P([0-9]+D(T(([0-9]+H([0-9]+M)?(([0-9]+|[0-9]+(\\.[0-9]+)?)S)?)|([0-9]+M(([0-9]+|[0-9]+(\\.[0-9]+)?)S)?)|([0-9]+|[0-9]+(\\.[0-9]+)?)S))?)|T(([0-9]+H([0-9]+M)?(([0-9]+|[0-9]+(\\.[0-9]+)?)S)?)|([0-9]+M(([0-9]+|[0-9]+(\\.[0-9]+)?)S)?)|([0-9]+|[0-9]+(\\.[0-9]+)?)S)$"
+    },
+    "DecimalDatatype": {
+      "description": "A real number expressed using a whole and optional fractional part separated by a period.",
+      "type": "number",
+      "pattern": "^(\\+|-)?([0-9]+(\\.[0-9]*)?|\\.[0-9]+)$"
+    },
+    "EmailAddressDatatype": {
+      "description": "An email address string formatted according to RFC 6531.",
+      "allOf": [
+        {"$ref": "#/definitions/StringDatatype"},
+        {
+          "type": "string",
+          "format": "email",
+          "pattern": "^.+@.+$"
+        }
+      ]     
+    },
+    "HostnameDatatype": {
+      "description": "An internationalized Internet host name string formatted according to section 2.3.2.3 of RFC5890.",
+      "allOf": [
+        {"$ref": "#/definitions/StringDatatype"},
+        {
+          "type": "string",
+          "format": "idn-hostname"
+        }
+      ]     
+    },
+    "IntegerDatatype": {
+      "description": "A whole number value.",
+      "type": "integer"
+    },
+    "IPV4AddressDatatype": {
+      "description": "An Internet Protocol version 4 address represented using dotted-quad syntax as defined in section 3.2 of RFC2673.",
+      "type": "string",
+      "format": "ipv4",
+      "pattern": "^((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])\\.){3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])$"
+    },
+    "IPV6AddressDatatype": {
+      "description": "An Internet Protocol version 6 address represented using the syntax defined in section 2.2 of RFC3513.",
+      "type": "string",
+      "format": "ipv6",
+      "pattern": "^(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|[fF][eE]80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::([fF]{4}(:0{1,4}){0,1}:){0,1}((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]).){3,3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]).){3,3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]))$"
+    },
+    "MarkupLineDatatype": {
+      "description": "",
+      "type": "string",
+      "pattern": "^[^\n]+$"
+    },
+    "MarkupMultilineDatatype": {
+      "description": "",
+      "type": "string"
+    },
+    "NonNegativeIntegerDatatype": {
+      "description": "An integer value that is equal to or greater than 0.",
+      "allOf": [
+        {"$ref": "#/definitions/IntegerDatatype"},
+        {
+          "type": "number",
+          "minimum": 0
+        }
+      ]
+    },
+    "PositiveIntegerDatatype": {
+      "description": "An integer value that is greater than 0.",
+      "allOf": [
+        {"$ref": "#/definitions/IntegerDatatype"},
+        {
+          "type": "number",
+          "minimum": 1
+        }
+      ]
+    },
+    "StringDatatype": {
+      "description": "A non-empty string with leading and trailing whitespace disallowed. Whitespace is: U+9, U+10, U+32 or [ \n\t]+",
+      "type": "string",
+      "pattern": "^\\S(.*\\S)?$"
+    },
+    "TokenDatatype": {
+      "description": "A non-colonized name as defined by XML Schema Part 2: Datatypes Second Edition. https://www.w3.org/TR/xmlschema11-2/#NCName.",
+      "type": "string",
+      "pattern": "^(\\p{L}|_)(\\p{L}|\\p{N}|[.\\-_])*$"
+    },
+    "URIDatatype": {
+      "description": "A universal resource identifier (URI) formatted according to RFC3986.",
+      "type": "string",
+      "format": "uri",
+      "pattern": "^[a-zA-Z][a-zA-Z0-9+\\-.]+:.+$"
+    },
+    "URIReferenceDatatype": {
+      "description": "A URI Reference, either a URI or a relative-reference, formatted according to section 4.1 of RFC3986.",
+      "type": "string",
+      "format": "uri-reference"
+    },
+    "UUIDDatatype": {
+      "description": "A type 4 ('random' or 'pseudorandom') or type 5 UUID per RFC 4122.",
+      "type": "string",
+      "pattern": "^[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-[45][0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}$"
+    },
+    "YearMonthDurationDatatype": {
+      "description": "An amount of time quantified in years and months based on ISO-8601 durations (see also RFC3339 appendix A).",
+      "type": "string",
+      "format": "duration",
+      "pattern": "^-?P([0-9]+Y([0-9]+M)?)|[0-9]+M$"
+    }
+  }
+}
diff --git a/schema/xml/metaschema-datatypes.xsd b/schema/xml/metaschema-datatypes.xsd
new file mode 100644
index 000000000..722ff2cbc
--- /dev/null
+++ b/schema/xml/metaschema-datatypes.xsd
@@ -0,0 +1,269 @@
+<?xml version="1.0" encoding="utf-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
+	elementFormDefault="qualified">
+
+	<xs:simpleType name="Base64Datatype">
+		<xs:annotation>
+			<xs:documentation>Binary data encoded using the Base 64 encoding algorithm
+				as defined by RFC4648.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:base64Binary">
+			<xs:pattern value="[0-9A-Za-z+/]+={0,2}">
+				<xs:annotation>
+					<xs:documentation>A string with at least one character and no
+						leading or trailing whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="BooleanDatatype">
+		<xs:annotation>
+			<xs:documentation>A binary value that is either: true (or 1) or false (or 0).</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:boolean">
+			<xs:pattern value="true|1|false|0"/>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="DateDatatype">
+		<xs:annotation>
+			<xs:documentation>A string representing a 24-hour period with an optional timezone.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:date">
+			<xs:pattern value="(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))(Z|[+-][0-9]{2}:[0-9]{2})?"/>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="DateWithTimezoneDatatype">
+		<xs:annotation>
+			<xs:documentation>A string representing a 24-hour period with a required timezone.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="DateDatatype">
+			<xs:pattern value="(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))(Z|[+-][0-9]{2}:[0-9]{2})"/>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="DateTimeDatatype">
+		<xs:annotation>
+			<xs:documentation>A string representing a point in time with an optional timezone.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:dateTime">
+			<xs:pattern value="(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])(\.[0-9]*[1-9])?(Z|(-((0[0-9]|1[0-2]):00|0[39]:30)|\+((0[0-9]|1[0-4]):00|(0[34569]|10):30|(0[58]|12):45)))?"/>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="DateTimeWithTimezoneDatatype">
+		<xs:annotation>
+			<xs:documentation>A string representing a point in time with a required timezone.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="DateTimeDatatype">
+			<xs:pattern value="(((2000|2400|2800|(19|2[0-9](0[48]|[2468][048]|[13579][26])))-02-29)|(((19|2[0-9])[0-9]{2})-02-(0[1-9]|1[0-9]|2[0-8]))|(((19|2[0-9])[0-9]{2})-(0[13578]|10|12)-(0[1-9]|[12][0-9]|3[01]))|(((19|2[0-9])[0-9]{2})-(0[469]|11)-(0[1-9]|[12][0-9]|30)))T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])(\.[0-9]*[1-9])?(Z|(-((0[0-9]|1[0-2]):00|0[39]:30)|\+((0[0-9]|1[0-4]):00|(0[34569]|10):30|(0[58]|12):45)))"/>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="DayTimeDurationDatatype">
+		<xs:annotation>
+			<xs:documentation>An amount of time quantified in days, hours, minutes, and seconds.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:duration">
+			<xs:pattern value="-?P([0-9]+D(T(([0-9]+H([0-9]+M)?(([0-9]+|[0-9]+(\.[0-9]+)?)S)?)|([0-9]+M(([0-9]+|[0-9]+(\.[0-9]+)?)S)?)|([0-9]+|[0-9]+(\.[0-9]+)?)S))?)|T(([0-9]+H([0-9]+M)?(([0-9]+|[0-9]+(\.[0-9]+)?)S)?)|([0-9]+M(([0-9]+|[0-9]+(\.[0-9]+)?)S)?)|([0-9]+|[0-9]+(\.[0-9]+)?)S)"/>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="DecimalDatatype">
+		<xs:annotation>
+			<xs:documentation>A real number expressed using a whole and optional fractional part
+				separated by a period.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:decimal">
+			<xs:pattern value="\S(.*\S)?">
+				<xs:annotation>
+					<xs:documentation>This pattern ensures that leading and trailing whitespace is
+						disallowed. This helps to even the user experience between implementations
+						related to whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="EmailAddressDatatype">
+		<xs:annotation>
+			<xs:documentation>An email address string formatted according to RFC 6531.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="StringDatatype">
+			<xs:pattern value=".+@.+">
+				<!-- TODO: Need a better pattern. -->
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="HostnameDatatype">
+		<xs:annotation>
+			<xs:documentation>A host name</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="StringDatatype">
+			<!-- TODO: Need a good hostname pattern -->
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="IntegerDatatype">
+		<xs:annotation>
+			<xs:documentation>A whole number value.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:integer">
+			<xs:pattern value="\S(.*\S)?">
+				<xs:annotation>
+					<xs:documentation>This pattern ensures that leading and trailing whitespace is
+						disallowed. This helps to even the user experience between implementations
+						related to whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="IPV4AddressDatatype">
+		<xs:annotation>
+			<xs:documentation>An Internet Protocol version 4 address represented using
+				dotted-quad syntax as defined in section 3.2 of RFC2673.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="StringDatatype">
+			<xs:pattern value="((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]).){3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])" />
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="IPV6AddressDatatype">
+		<xs:annotation>
+			<xs:documentation>An Internet Protocol version 6 address represented using
+				the syntax defined in section 2.2 of RFC3513.</xs:documentation>
+			<xs:documentation>This is based on the pattern provided here:
+				https://stackoverflow.com/questions/53497/regular-expression-that-matches-valid-ipv6-addresses
+				with some customizations.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="StringDatatype">
+			<xs:pattern
+				value="(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|[fF][eE]80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::([fF]{4}(:0{1,4}){0,1}:){0,1}((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]).){3,3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]).){3,3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]))" />
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="NonNegativeIntegerDatatype">
+		<xs:annotation>
+			<xs:documentation>An integer value that is equal to or greater than 0.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:nonNegativeInteger">
+			<xs:pattern value="\S(.*\S)?">
+				<xs:annotation>
+					<xs:documentation>This pattern ensures that leading and trailing whitespace is
+						disallowed. This helps to even the user experience between implementations
+						related to whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="PositiveIntegerDatatype">
+		<xs:annotation>
+			<xs:documentation>An integer value that is greater than 0.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:positiveInteger">
+			<xs:pattern value="\S(.*\S)?">
+				<xs:annotation>
+					<xs:documentation>This pattern ensures that leading and trailing whitespace is
+						disallowed. This helps to even the user experience between implementations
+						related to whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="StringDatatype">
+		<xs:annotation>
+			<xs:documentation>A non-empty string of unicode characters with leading and trailing whitespace
+				disallowed. Whitespace is: U+9, U+10, U+32 or [ \n\t]+</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:string">
+			<xs:annotation>
+				<xs:documentation>The OSCAL 'string' datatype restricts the XSD type by prohibiting leading 
+					and trailing whitespace, and something (not only whitespace) is required.</xs:documentation>
+			</xs:annotation>
+			<xs:whiteSpace value="preserve" />
+			<xs:pattern value="\S(.*\S)?">
+				<xs:annotation>
+					<xs:documentation>This pattern ensures that leading and trailing whitespace is
+						disallowed. This helps to even the user experience between implementations
+						related to whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+	
+	<xs:simpleType name="TokenDatatype">
+		<xs:annotation>
+			<!--<xs:documentation>Matching XSD NCName, except whitespace is not collapsed.</xs:documentation> -->
+			<xs:documentation>A non-empty, non-colonized name as defined by XML Schema Part 2: Datatypes
+				Second Edition (https://www.w3.org/TR/xmlschema11-2/#NCName), with leading and trailing
+				whitespace disallowed.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="StringDatatype">
+			<!-- value="(\p{L}|_)(\p{L}|\p{N}|[.\-_]|\xb7|[#x0300-#x036F#x203F-#x2040])*"> -->
+			<xs:pattern value="(\p{L}|_)(\p{L}|\p{N}|[.\-_])*">
+				<xs:annotation>
+					<!--<xs:documentation>An XML initial character (but not colon), followed 
+						by any XML name character (but not colon).</xs:documentation> -->
+					<xs:documentation>A single token may not contain whitespace.
+					</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="URIDatatype">
+		<xs:annotation>
+			<xs:documentation>A universal resource identifier (URI) formatted according to RFC3986.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:anyURI">
+			<xs:pattern value="[a-zA-Z][a-zA-Z0-9+\-.]+:.*\S">
+				<xs:annotation>
+					<xs:documentation>Requires a scheme with colon per RFC 3986.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="URIReferenceDatatype">
+		<xs:annotation>
+			<xs:documentation>A URI Reference, either a URI or a relative-reference, formatted according to section 4.1 of RFC3986.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="xs:anyURI">
+			<xs:pattern value="\S(.*\S)?">
+				<xs:annotation>
+					<xs:documentation>This pattern ensures that leading and trailing whitespace is
+						disallowed. This helps to even the user experience between implementations
+						related to whitespace.</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="UUIDDatatype">
+		<xs:annotation>
+			<xs:documentation>A type 4 ('random' or 'pseudorandom') or type 5 UUID per RFC
+				4122.</xs:documentation>
+		</xs:annotation>
+		<xs:restriction base="StringDatatype">
+			<xs:pattern value="[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-[45][0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}">
+				<xs:annotation>
+					<xs:documentation>A sequence of 8-4-4-4-12 hex digits, with extra
+						constraints in the 13th and 17-18th places for version 4 and 5
+					</xs:documentation>
+				</xs:annotation>
+			</xs:pattern>
+		</xs:restriction>
+	</xs:simpleType>
+
+	<xs:simpleType name="YearMonthDurationDatatype">
+		<xs:restriction base="xs:duration">
+			<xs:pattern value="-?P([0-9]+Y([0-9]+M)?)|[0-9]+M"/>
+		</xs:restriction>
+	</xs:simpleType>
+</xs:schema>
diff --git a/schema/xml/metaschema-markup-line.xsd b/schema/xml/metaschema-markup-line.xsd
new file mode 100644
index 000000000..c430944f9
--- /dev/null
+++ b/schema/xml/metaschema-markup-line.xsd
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
+  
+  <xs:include schemaLocation="metaschema-prose-base.xsd"/>
+
+
+  <xs:complexType name="MarkupLineDatatype" mixed="true">
+    <xs:complexContent>
+      <xs:extension base="inlineMarkupType"/>
+    </xs:complexContent>
+  </xs:complexType>
+</xs:schema>
diff --git a/schema/xml/metaschema-markup-multiline.xsd b/schema/xml/metaschema-markup-multiline.xsd
new file mode 100644
index 000000000..33d35f539
--- /dev/null
+++ b/schema/xml/metaschema-markup-multiline.xsd
@@ -0,0 +1,95 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
+  
+  <xs:include schemaLocation="metaschema-prose-base.xsd"/>
+
+  <xs:complexType name="MarkupMultilineDatatype">
+    <xs:choice minOccurs="1" maxOccurs="unbounded">
+      <xs:group ref="blockElementGroup"/>
+    </xs:choice>
+  </xs:complexType>
+
+  <xs:group name="blockElementGroup">
+    <xs:choice>
+      <xs:element name="h1"    type="inlineMarkupType"/>
+      <xs:element name="h2"    type="inlineMarkupType"/>
+      <xs:element name="h3"    type="inlineMarkupType"/>
+      <xs:element name="h4"    type="inlineMarkupType"/>
+      <xs:element name="h5"    type="inlineMarkupType"/>
+      <xs:element name="h6"    type="inlineMarkupType"/>
+      <xs:element name="p"     type="inlineMarkupType"/>
+      <xs:element name="ul"    type="listType"/>
+      <xs:element name="ol"    type="listType"/>
+      <xs:element name="pre"   type="preformattedType"/>
+      <xs:element name="table" type="tableType"/>
+      <xs:element name="img" type="imageType"/>
+      <!-- TODO: need to add support for blockquote, which can contain block elements. usnistgov/metaschema#70 -->
+    </xs:choice>
+  </xs:group>
+
+  <!--
+    headers: phrase inline markup, a, insert (phrase)
+    p: phrase inline markup, a, insert, img (phrase+img)
+    li: phrase inline markup, a, insert, img (phrase+img)
+    pre: phrase inline markup, a, insert (phrase)
+    td th: phrase inline markup, a, insert, img (phrase+img)
+  -->
+
+  <xs:complexType name="preformattedType" mixed="true">
+    <xs:complexContent>
+      <xs:extension base="inlineMarkupType">
+        <xs:annotation>
+          <xs:documentation>The content model is the same as inlineMarkupType, but line endings need
+            to be preserved, since this is preformatted.</xs:documentation>
+        </xs:annotation>
+      </xs:extension>
+    </xs:complexContent>
+  </xs:complexType>
+
+  <xs:complexType name="listType">
+    <xs:sequence>
+      <xs:element name="li" type="listItemType" minOccurs="1" maxOccurs="unbounded"/>
+    </xs:sequence>
+  </xs:complexType>
+
+  <xs:complexType name="listItemType" mixed="true">
+    <!-- TODO: is this the correct construction? -->
+    <xs:choice minOccurs="0" maxOccurs="unbounded">
+      <xs:group ref="inlineMarkupGroup"/>
+      <xs:element name="ul" type="listType"/>
+      <xs:element name="ol" type="listType"/>
+    </xs:choice>
+  </xs:complexType>
+
+  <xs:complexType name="tableType">
+    <xs:sequence>
+      <xs:element maxOccurs="unbounded" name="tr" type="tableRowType"/>
+    </xs:sequence>
+  </xs:complexType>
+
+  <xs:complexType name="tableRowType">
+    <!-- QUESTION: Should we allow TH and TD to be mixed? -->
+    <xs:choice minOccurs="1" maxOccurs="unbounded">
+      <xs:element name="td" type="tableCellType" maxOccurs="unbounded"/>
+      <xs:element name="th" type="tableCellType" maxOccurs="unbounded"/>
+    </xs:choice>
+  </xs:complexType>
+
+  <xs:complexType name="tableCellType" mixed="true">
+    <xs:complexContent>
+      <!-- TODO: consider adding a choice between the inline or paragraphs. We need to figure out what is supported in Markdown. -->
+      <xs:extension base="inlineMarkupType">
+        <!-- TODO: need to add support for alignment. usnistgov/metaschema#70 -->
+        <xs:attribute name="align" type="alignType" default="left"/>
+      </xs:extension>
+    </xs:complexContent>
+  </xs:complexType>
+
+  <xs:simpleType name="alignType">
+    <xs:restriction base="xs:token">
+      <xs:enumeration value="left"/>
+      <xs:enumeration value="center"/>
+      <xs:enumeration value="right"/>
+    </xs:restriction>
+  </xs:simpleType>
+</xs:schema>
diff --git a/schema/xml/metaschema-prose-base.xsd b/schema/xml/metaschema-prose-base.xsd
new file mode 100644
index 000000000..2c24ceb31
--- /dev/null
+++ b/schema/xml/metaschema-prose-base.xsd
@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
+  <xs:complexType name="inlineMarkupType" mixed="true">
+    <xs:choice minOccurs="0" maxOccurs="unbounded">
+      <xs:group ref="inlineMarkupGroup"/>
+    </xs:choice>
+  </xs:complexType>
+  
+  <xs:group name="inlineMarkupGroup">
+    <xs:choice>
+      <xs:element name="a" type="anchorType"/>
+      <xs:element name="insert" type="insertType"/>
+      <xs:group ref="phraseMarkupGroup"/>
+    </xs:choice>
+  </xs:group>
+  <xs:group name="phraseMarkupGroup">
+    <xs:choice>
+      <xs:element name="code" type="inlineMarkupType"/>
+      <xs:element name="em" type="inlineMarkupType"/>
+      <xs:element name="i" type="inlineMarkupType"/>
+      <xs:element name="b" type="inlineMarkupType"/>
+      <xs:element name="strong" type="inlineMarkupType"/>
+      <xs:element name="sub" type="inlineMarkupType"/>
+      <xs:element name="sup" type="inlineMarkupType"/>
+      <xs:element name="q" type="inlineMarkupType"/>
+      <xs:element name="img" type="imageType"/>
+    </xs:choice>
+  </xs:group>
+  <xs:complexType name="imageType">
+    <xs:attribute name="alt" type="xs:string"/>
+    <xs:attribute name="src" use="required" type="xs:anyURI"/>
+  </xs:complexType>
+
+  <xs:complexType name="anchorType" mixed="true">
+    <xs:choice minOccurs="0" maxOccurs="unbounded">
+      <xs:group ref="phraseMarkupGroup"/>
+    </xs:choice>
+    <xs:attribute name="href" type="xs:anyURI"/>
+  </xs:complexType>
+
+  <!--
+    A value to be assigned by responder via parameter
+    (a parameter must be available)
+  -->
+  <xs:complexType name="insertType">
+    <xs:annotation>
+      <xs:documentation>An insert can be used to identify a placeholder for dynamically inserting text related to a specific object, which is referenced by the object's identifier using an <code>id-ref</code>. This insert mechanism allows the selection of which text value from the object to dynamically include based on the application's display requirements.</xs:documentation>
+    </xs:annotation>
+    <xs:attribute name="type" use="required" type="xs:NCName">
+      <xs:annotation>
+        <xs:documentation>The type of object to include from (e.g., parameter, control, component, role, etc.)</xs:documentation>
+      </xs:annotation>
+    </xs:attribute>
+    <xs:attribute name="id-ref" use="required" type="xs:NCName">
+      <xs:annotation>
+        <xs:documentation>The identity of the object to insert a value for. The identity will be selected from the index of objects of the specified <code>type</code>. The specific value to include is based on the application's display requirements, which will likely use a specific data element associated with the <code>type</code> (e.g., title, identifier, value, etc.) that is appropriate for the application.</xs:documentation>
+      </xs:annotation>
+    </xs:attribute>
+  </xs:complexType>
+
+  <!--
+    Within a selection, a choice - tbd
+    unlike 'value', choice may have inline stuff as well as 'assign' elements
+    choice = element choice { (assign | mix)* }
+  -->
+  <!--
+    IDs are required everywhere for now
+    idAttr      = attribute id { xsd:ID }
+  -->
+</xs:schema>
diff --git a/schema/xml/metaschema-prose-module.xsd b/schema/xml/metaschema-prose-module.xsd
new file mode 100644
index 000000000..e653c0537
--- /dev/null
+++ b/schema/xml/metaschema-prose-module.xsd
@@ -0,0 +1,5 @@
+<?xml version="1.1" encoding="UTF-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
+    <xs:include schemaLocation="metaschema-markup-line.xsd"/>
+    <xs:include schemaLocation="metaschema-markup-multiline.xsd"/>
+</xs:schema>