diff --git a/core/node.py b/core/node.py
index da9b4ff..0bab6f3 100644
--- a/core/node.py
+++ b/core/node.py
@@ -12,7 +12,7 @@ class Node:
     def __init__(self, Network, NodeID, Genesis, PoWDelay = 1):
         self.TipsSet = [Genesis]
         self.Ledger = [Genesis]
-        self.LedgerTranIDs = []
+        self.LedgerTranIDs = [0]
         self.Neighbours = []
         self.Network = Network
         self.Inbox = Inbox(self)
@@ -137,13 +137,17 @@ def parse(self, Packet, Time):
         Not fully implemented yet
         Simply makes a copy of the transaction and then calls the solidifier
         """
-        Packet.Data = Packet.Data.copy()
         self.solidify(Packet, Time)
-    
+
     def solidify(self, Packet, Time):
         """
         Not implemented yet, just calls the booker
         """
+        Packet.Data = Packet.Data.copy(self)
+        Tran = Packet.Data
+        assert isinstance(Tran, Transaction)
+        Tran.solidify()
+                
         self.book(Packet, Time)
 
     def book(self, Packet, Time):
diff --git a/core/transaction.py b/core/transaction.py
index a83bcbe..afd2b28 100644
--- a/core/transaction.py
+++ b/core/transaction.py
@@ -18,6 +18,7 @@ def __init__(self, IssueTime, Parents, Node, Network, Work=0, Index=None, Visibl
         self.Work = Work
         self.AWeight = Work
         self.LastAWUpdate = self
+        self.Solid = True
         if Node:
             self.NodeID = Node.NodeID # signature of issuing node
             self.Eligible = False
@@ -69,14 +70,39 @@ def updateAW(self, Node, updateTran=None, Work=None):
             if not p.Confirmed and p.LastAWUpdate != updateTran:
                 p.updateAW(Node, updateTran, Work)
     
-    def copy(self):
+    def copy(self, Node):
         Tran = copy(self)
-        Tran.Children = []
+        Tran.Solid = True
+        parentIDs = [p.Index for p in Tran.Parents]
+        parents = []
+        for pID in parentIDs:
+            if pID in Node.LedgerTranIDs:
+                parents.append(Node.Ledger[Node.LedgerTranIDs.index(pID)])
+        Tran.Parents = parents
+        childrenIDs = [c.Index for c in Tran.Children]
+        children = []
+        for cID in childrenIDs:
+            if cID in Node.LedgerTranIDs:
+                children.append(Node.Ledger[Node.LedgerTranIDs.index(cID)])
+        Tran.Children = children
         Tran.Eligible = False
         Tran.Confirmed = False
-
         return Tran
 
+    def solidify(self):
+        solidParents = [p for p in self.Parents if p.Solid]
+        if len(solidParents)==1:
+            if self.Parents[0].Index==0: # if parent is genesis
+                self.Solid = True
+        if len(solidParents)==2: # if two solid parents
+            self.Solid = True
+        for c in self.Children:
+            assert isinstance(c, Transaction)
+            if self not in c.Parents:
+                c.Parents.append(self)
+            c.solidify()
+
+
     def is_ready(self):
         for p in self.Parents:
             if not p.Eligible: