diff --git a/flatdata-generator/flatdata/generator/engine.py b/flatdata-generator/flatdata/generator/engine.py
index 76d892ce..bf6a6d9e 100644
--- a/flatdata-generator/flatdata/generator/engine.py
+++ b/flatdata-generator/flatdata/generator/engine.py
@@ -7,6 +7,7 @@
 
 from flatdata.generator.tree.builder import build_ast
 from flatdata.generator.tree.nodes.trivial.namespace import Namespace
+from flatdata.generator.tree.nodes.node import Node
 
 from .generators.cpp import CppGenerator
 from .generators.dot import DotGenerator
@@ -69,7 +70,7 @@ def render_python_module(self, module_name=None, archive_name=None, root_namespa
             if specified, archive type is returned along with the model
         :param root_namespace: Root namespace to pick in case of multiple top level namespaces.
         """
-        root_namespace = self._find_root_namespace(self.tree, root_namespace)
+        root_namespace = self._find_root_namespace(self.tree, archive_name, root_namespace)
         module_code = self.render("py")
         module = types.ModuleType(module_name if module_name is not None else root_namespace.name)
         #pylint: disable=exec-used
@@ -90,7 +91,7 @@ def _create_generator(cls, name):
         return generator_type()
 
     @staticmethod
-    def _find_root_namespace(tree, root_namespace=None):
+    def _find_root_namespace(tree, archive_name, root_namespace=None):
         root_children = tree.root.children
         root_namespaces = [
             child for child in root_children
@@ -103,6 +104,13 @@ def _find_root_namespace(tree, root_namespace=None):
                 if namespace.name == root_namespace:
                     return namespace
             raise RuntimeError("Invalid root namespace provided. Could not find root namespace in archive.")
+        elif archive_name:
+            for namespace in root_namespaces:
+                archive_path = namespace.name + Node.PATH_SEPARATOR + archive_name
+                archive_node = namespace.get(archive_path)
+                if archive_node is not None:
+                    return namespace
+            raise RuntimeError("Archive direct parent namespace is not a root namespace.")
         elif len(root_namespaces) > 1:
             raise RuntimeError("Ambiguous root namespace. Could not find root archive.")
 
diff --git a/flatdata-generator/flatdata/generator/tree/syntax_tree.py b/flatdata-generator/flatdata/generator/tree/syntax_tree.py
index 4369110f..51172057 100644
--- a/flatdata-generator/flatdata/generator/tree/syntax_tree.py
+++ b/flatdata-generator/flatdata/generator/tree/syntax_tree.py
@@ -39,6 +39,12 @@ def find(self, path):
         """
         return self._root.find(path)
 
+    def get(self, path, default=None):
+        """
+        Returns the node like find() does, but allows default value specification.
+        """
+        return self._root.get(path, default)
+
     def subtree(self, path):
         """
         Returns subtree of the given tree as a SyntaxTree
diff --git a/flatdata-py/tests/test_backward_compatibility.py b/flatdata-py/tests/test_backward_compatibility.py
index 7fffe87c..a1c5ee42 100644
--- a/flatdata-py/tests/test_backward_compatibility.py
+++ b/flatdata-py/tests/test_backward_compatibility.py
@@ -29,9 +29,25 @@ def test_instance_reading():
     check_signed_struct(archive.resource[0])
 
 
-def test_multi_namespace_instance_reading():
+def test_multi_namespace_instance_reading_implicit():
+    root_namespace = None
+    archive_name = "Archive"
+    module, archive_type = Engine(MULTI_NAMESPACE_TEST_SCHEMA).render_python_module(None, archive_name, root_namespace)
+    valid_data = {
+        "Archive.archive": ARCHIVE_SIGNATURE_PAYLOAD,
+        "Archive.archive.schema": module.backward_compatibility_Archive.schema().encode(),
+        "resource": RESOURCE_PAYLOAD,
+        "resource.schema": module.backward_compatibility_Archive.resource_schema('resource').encode()
+    }
+    archive = module.backward_compatibility_Archive(DictResourceStorage(valid_data))
+    check_signed_struct(archive.resource)
+    check_signed_struct(archive.resource[0])
+
+
+def test_multi_namespace_instance_reading_explicit():
     root_namespace = "backward_compatibility"
-    module = Engine(MULTI_NAMESPACE_TEST_SCHEMA).render_python_module(None, None, root_namespace)
+    archive_name = None
+    module = Engine(MULTI_NAMESPACE_TEST_SCHEMA).render_python_module(None, archive_name, root_namespace)
     valid_data = {
         "Archive.archive": ARCHIVE_SIGNATURE_PAYLOAD,
         "Archive.archive.schema": module.backward_compatibility_Archive.schema().encode(),