diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.cpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.cpp
index 40ce820bdf28..83c7366d3c29 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.cpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.cpp
@@ -34,16 +34,32 @@ template <UltraFlavor Flavor> UltraVerifier_<Flavor> UltraComposer_<Flavor>::cre
 }
 
 template <UltraFlavor Flavor>
-ProtoGalaxyProver_<Flavor> UltraComposer_<Flavor>::create_folding_prover(std::vector<Instance> instances)
+ProtoGalaxyProver_<Flavor> UltraComposer_<Flavor>::create_folding_prover(
+    std::vector<std::shared_ptr<Instance>> instances)
 {
-    for (size_t i = 0; i < instances.size(); i++) {
-        instances[i].index = i;
+    uint32_t idx = 0;
+    for (const auto& inst : instances) {
+        inst->index = idx;
+        idx++;
     }
     ProtoGalaxyProver_<Flavor> output_state(instances);
 
     return output_state;
 }
 
+template <UltraFlavor Flavor>
+ProtoGalaxyVerifier_<Flavor> UltraComposer_<Flavor>::create_folding_verifier(
+    std::vector<std::shared_ptr<Instance>> instances)
+{
+    std::vector<std::shared_ptr<VerificationKey>> vks;
+    for (const auto& inst : instances) {
+        vks.emplace_back(inst->compute_verification_key());
+    }
+    ProtoGalaxyVerifier_<Flavor> output_state(vks);
+
+    return output_state;
+}
+
 template class UltraComposer_<honk::flavor::Ultra>;
 template class UltraComposer_<honk::flavor::UltraGrumpkin>;
 template class UltraComposer_<honk::flavor::GoblinUltra>;
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.hpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.hpp
index e676dc3fa142..f5476754870a 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.hpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/composer/ultra_composer.hpp
@@ -1,5 +1,4 @@
 #pragma once
-
 #include "barretenberg/honk/instance/instance.hpp"
 #include "barretenberg/honk/proof_system/protogalaxy_prover.hpp"
 #include "barretenberg/honk/proof_system/protogalaxy_verifier.hpp"
@@ -75,8 +74,8 @@ template <UltraFlavor Flavor> class UltraComposer_ {
     UltraProver_<Flavor> create_prover(Instance&);
     UltraVerifier_<Flavor> create_verifier(Instance&);
 
-    ProtoGalaxyProver_<Flavor> create_folding_prover(std::vector<Instance&>);
-    ProtoGalaxyVerifier_<Flavor> create_folding_verifier(std::vector<Instance&>);
+    ProtoGalaxyProver_<Flavor> create_folding_prover(std::vector<std::shared_ptr<Instance>>);
+    ProtoGalaxyVerifier_<Flavor> create_folding_verifier(std::vector<std::shared_ptr<Instance>>);
 };
 extern template class UltraComposer_<honk::flavor::Ultra>;
 // TODO: the UltraGrumpkin flavor still works on BN254 because plookup needs to be templated to be able to construct
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/instance.hpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/instance.hpp
index aa8389cca352..a2230df10bb2 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/instance.hpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/instance.hpp
@@ -13,10 +13,11 @@
 #include <vector>
 namespace proof_system::honk {
 // Need verifier instance as well
-// An Instance is created from a Circuit and we initialise all the data structure that rely on information from a
+// An Instance is created from a Circuit and we ini tialise all the data structure that rely on information from a
 // circuit Then a Prover and a Verifier is created from an Instance or several instances and each manages their own
 // polynomials
 // The responsability of a Prover is to commit, add to transcript while the Instance manages its polynomials
+// TODO: we might wanna have a specialisaition of the Instance class for the Accumulator
 template <UltraFlavor Flavor> class Instance_ {
   public:
     using Circuit = typename Flavor::CircuitBuilder;
@@ -37,6 +38,10 @@ template <UltraFlavor Flavor> class Instance_ {
     std::shared_ptr<CommitmentKey> commitment_key;
 
     ProverPolynomials prover_polynomials;
+
+    // After instances have been folded, the pub_inputs_offset will become irrelevant as it's used for computing the 4th
+    // wire polynomial and a folded instance does not care about wires anymore.
+    // Furthermore, folding limits us to having the same number of public inputs.
     std::vector<FF> public_inputs;
     size_t pub_inputs_offset;
 
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/verifier_instance.hpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/verifier_instance.hpp
index 0ada88d70857..e647022be3ee 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/verifier_instance.hpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/instance/verifier_instance.hpp
@@ -1,6 +1,9 @@
+#pragma once
 #include "barretenberg/proof_system/flavor/flavor.hpp"
+#include "barretenberg/proof_system/relations/relation_parameters.hpp"
 namespace proof_system::honk {
 template <UltraFlavor Flavor> class VerifierInstance_ {
+  public:
     using FF = typename Flavor::FF;
     using VerificationKey = typename Flavor::VerificationKey;
     using FoldingParameters = typename Flavor::FoldingParameters;
@@ -8,7 +11,9 @@ template <UltraFlavor Flavor> class VerifierInstance_ {
     std::shared_ptr<VerificationKey> verification_key;
     std::vector<FF> public_inputs;
     size_t pub_inputs_offset;
+    size_t public_input_size;
     size_t circuit_size;
+    RelationParameters<FF> relation_parameters;
     FoldingParameters folding_params;
     size_t index;
 };
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/folding_result.hpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/folding_result.hpp
index d8e5d4ab53a8..a504a515566c 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/folding_result.hpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/folding_result.hpp
@@ -1,3 +1,4 @@
+#pragma once
 #include "barretenberg/proof_system/flavor/flavor.hpp"
 namespace proof_system::honk {
 template <UltraFlavor Flavor> struct ProverFoldingResult {
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.cpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.cpp
index 36194da44134..ba70a46d0ed8 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.cpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.cpp
@@ -2,7 +2,7 @@
 #include "barretenberg/proof_system/flavor/flavor.hpp"
 namespace proof_system::honk {
 template <UltraFlavor Flavor>
-ProtoGalaxyProver_<Flavor>::ProtoGalaxyProver_(std::vector<Instance&> insts)
+ProtoGalaxyProver_<Flavor>::ProtoGalaxyProver_(std::vector<std::shared_ptr<Instance>> insts)
     : instances(insts)
 {}
 
@@ -12,28 +12,32 @@ ProtoGalaxyProver_<Flavor>::ProtoGalaxyProver_(std::vector<Instance&> insts)
 //  - add the relation parameters involved in computing the instances polynomials to the transcript
 template <UltraFlavor Flavor> void ProtoGalaxyProver_<Flavor>::prepare_for_folding()
 {
-    for (const Instance& instance : instances) {
-        instance.initialise_prover_polynomials();
+    for (const auto& instance : instances) {
+        instance->initialise_prover_polynomials();
 
-        const auto instance_index = std::string(instance.index);
-        const auto circuit_size = static_cast<uint32_t>(instance.proving_key->circuit_size);
-        const auto num_public_inputs = static_cast<uint32_t>(instance.proving_key->num_public_inputs);
+        const auto instance_index = std::to_string(instance->index);
+        const auto circuit_size = static_cast<uint32_t>(instance->proving_key->circuit_size);
+        const auto num_public_inputs = static_cast<uint32_t>(instance->proving_key->num_public_inputs);
 
         transcript.send_to_verifier(instance_index + "_circuit_size", circuit_size);
         transcript.send_to_verifier(instance_index + "_public_input_size", num_public_inputs);
-        transcript.send_to_verifier(instance_index + "_pub_inputs_offset",
-                                    static_cast<uint32_t>(instance.pub_inputs_offset));
+        // transcript.send_to_verifier(instance_index + "_pub_inputs_offset",
+        //                             static_cast<uint32_t>(instance.pub_inputs_offset));
 
-        for (size_t i = 0; i < instance.proving_key->num_public_inputs; ++i) {
-            auto public_input_i = instance.public_inputs[i];
+        for (size_t i = 0; i < instance->proving_key->num_public_inputs; ++i) {
+            auto public_input_i = instance->public_inputs[i];
             transcript.send_to_verifier(instance_index + "_public_input_" + std::to_string(i), public_input_i);
         }
 
         auto eta = transcript.get_challenge(instance_index + "_eta");
-        instance.compute_sorted_accumulator_polynomials(eta);
+        instance->compute_sorted_accumulator_polynomials(eta);
         auto [beta, gamma] = transcript.get_challenges(instance_index + "_beta", instance_index + "_gamma");
-        instance.compute_grand_product_polynomials(beta, gamma);
+        instance->compute_grand_product_polynomials(beta, gamma);
     }
 }
 
+template class ProtoGalaxyProver_<honk::flavor::Ultra>;
+template class ProtoGalaxyProver_<honk::flavor::UltraGrumpkin>;
+template class ProtoGalaxyProver_<honk::flavor::GoblinUltra>;
+
 } // namespace proof_system::honk
\ No newline at end of file
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.hpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.hpp
index 888599b4f6b5..a77f0d047125 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.hpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_prover.hpp
@@ -1,6 +1,10 @@
+#pragma once
+#include "barretenberg/honk/flavor/goblin_ultra.hpp"
+#include "barretenberg/honk/flavor/ultra.hpp"
+#include "barretenberg/honk/flavor/ultra_grumpkin.hpp"
 #include "barretenberg/honk/instance/instance.hpp"
+#include "barretenberg/honk/proof_system/folding_result.hpp"
 #include "barretenberg/proof_system/flavor/flavor.hpp"
-#include "barretenberg/proof_system/folding_result.hpp"
 namespace proof_system::honk {
 template <UltraFlavor Flavor> class ProtoGalaxyProver_ {
   public:
@@ -8,16 +12,19 @@ template <UltraFlavor Flavor> class ProtoGalaxyProver_ {
     using Instance = Instance_<Flavor>;
     using ProverPolynomials = typename Flavor::ProverPolynomials;
 
-    std::vector<Instance&> instances;
+    std::vector<std::shared_ptr<Instance>> instances;
 
     ProverTranscript<FF> transcript;
 
-    explicit ProtoGalaxyProver_(std::vector<Instance&>);
+    explicit ProtoGalaxyProver_(std::vector<std::shared_ptr<Instance>>);
 
     void prepare_for_folding();
 
-    // TODO: implement this function
     ProverFoldingResult<Flavor> fold_instances();
 };
+
+extern template class ProtoGalaxyProver_<honk::flavor::Ultra>;
+extern template class ProtoGalaxyProver_<honk::flavor::UltraGrumpkin>;
+extern template class ProtoGalaxyProver_<honk::flavor::GoblinUltra>;
 // the folding prover returns the new prover polynomials and the new public inputs(does the verifier do anything)
 } // namespace proof_system::honk
\ No newline at end of file
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.cpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.cpp
index c9bd7e2b2a0c..ca0507df274c 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.cpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.cpp
@@ -1,9 +1,48 @@
 #include "protogalaxy_verifier.hpp"
+#include "barretenberg/honk/utils/grand_product_delta.hpp"
 namespace proof_system::honk {
 template <UltraFlavor Flavor>
-ProtoGalaxyVerifier_<Flavor>::ProtoGalaxyVerifier_(std::vector<VerificationKey> vks, std::vector<uint8_t> proof_data)
+ProtoGalaxyVerifier_<Flavor>::ProtoGalaxyVerifier_(std::vector<std::shared_ptr<VerificationKey>> vks)
+{
+    uint32_t idx = 0;
+    for (const auto& vk : vks) {
+        VerifierInstance inst;
+        inst.verification_key = std::move(vk);
+        inst.index = idx;
+        verifier_instances.emplace_back(inst);
+        idx++;
+    }
+}
 
+template <UltraFlavor Flavor>
+VerifierFoldingResult<Flavor> ProtoGalaxyVerifier_<Flavor>::fold_public_parameters(std::vector<uint8_t> fold_data)
 {
-    transcript = VerifierTranscript<FF>{ proof_data };
+    transcript = VerifierTranscript<FF>{ fold_data };
+    for (auto& inst : verifier_instances) {
+        auto idx = std::to_string(inst.index);
+        inst.circuit_size = transcript.template receive_from_prover<uint32_t>(idx + "_circuit_size");
+        inst.public_input_size = transcript.template receive_from_prover<uint32_t>(idx + "_public_input_size");
+        inst.pub_inputs_offset = transcript.template receive_from_prover<uint32_t>(idx + "_pub_inputs_offset");
+
+        for (size_t i = 0; i < inst.public_input_size; ++i) {
+            auto public_input_i =
+                transcript.template receive_from_prover<FF>(idx + "public_input_" + std::to_string(i));
+            inst.public_inputs.emplace_back(public_input_i);
+        }
+        auto eta = transcript.get_challenge(idx + "_eta");
+        auto [beta, gamma] = transcript.get_challenges(idx + "_beta", idx + "_gamma");
+        const FF public_input_delta = compute_public_input_delta<Flavor>(
+            inst.public_inputs, beta, gamma, inst.circuit_size, inst.pub_inputs_offset);
+        const FF lookup_grand_product_delta = compute_lookup_grand_product_delta<FF>(beta, gamma, inst.circuit_size);
+        inst.relation_parameters =
+            RelationParameters<FF>{ eta, beta, gamma, public_input_delta, lookup_grand_product_delta };
+        verifier_instances.emplace_back(inst);
+    }
+    VerifierFoldingResult<Flavor> res;
+    return res;
 }
+
+template class ProtoGalaxyVerifier_<honk::flavor::Ultra>;
+template class ProtoGalaxyVerifier_<honk::flavor::UltraGrumpkin>;
+template class ProtoGalaxyVerifier_<honk::flavor::GoblinUltra>;
 } // namespace proof_system::honk
\ No newline at end of file
diff --git a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.hpp b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.hpp
index df4146b67db6..ce4236e85b13 100644
--- a/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.hpp
+++ b/circuits/cpp/barretenberg/cpp/src/barretenberg/honk/proof_system/protogalaxy_verifier.hpp
@@ -1,16 +1,26 @@
+#pragma once
+#include "barretenberg/honk/flavor/goblin_ultra.hpp"
+#include "barretenberg/honk/flavor/ultra.hpp"
+#include "barretenberg/honk/flavor/ultra_grumpkin.hpp"
+#include "barretenberg/honk/instance/verifier_instance.hpp"
+#include "barretenberg/honk/proof_system/folding_result.hpp"
 #include "barretenberg/honk/transcript/transcript.hpp"
 #include "barretenberg/proof_system/flavor/flavor.hpp"
-#include "barretenberg/proof_system/folding_result.hpp"
 
 namespace proof_system::honk {
 template <UltraFlavor Flavor> class ProtoGalaxyVerifier_ {
   public:
     using FF = typename Flavor::FF;
     using VerificationKey = typename Flavor::VerificationKey;
+    using VerifierInstance = VerifierInstance_<Flavor>;
     std::vector<VerifierInstance> verifier_instances;
     VerifierTranscript<FF> transcript;
 
-    explicit ProtoGalaxyVerifier_(std::vector<VerificationKey> vks);
-    VerifierFoldingResult<Flavor> fold_public_parameters();
+    explicit ProtoGalaxyVerifier_(std::vector<std::shared_ptr<VerificationKey>> vks);
+    VerifierFoldingResult<Flavor> fold_public_parameters(std::vector<uint8_t> fold_data);
 };
+
+extern template class ProtoGalaxyVerifier_<honk::flavor::Ultra>;
+extern template class ProtoGalaxyVerifier_<honk::flavor::UltraGrumpkin>;
+extern template class ProtoGalaxyVerifier_<honk::flavor::GoblinUltra>;
 } // namespace proof_system::honk
\ No newline at end of file