diff --git a/include/hsm/details/collect_states.h b/include/hsm/details/collect_states.h
index 1b7a6dd..b3f61cc 100644
--- a/include/hsm/details/collect_states.h
+++ b/include/hsm/details/collect_states.h
@@ -8,6 +8,7 @@
 #include <boost/hana/at.hpp>
 #include <boost/hana/basic_tuple.hpp>
 #include <boost/hana/flatten.hpp>
+#include <boost/hana/prepend.hpp>
 #include <boost/hana/transform.hpp>
 #include <boost/hana/type.hpp>
 
@@ -51,6 +52,12 @@ constexpr auto extractStateTypeids = [](auto transition) {
 };
 }
 
+constexpr auto extractParentAndState = [](auto transition) {
+    return bh::make_basic_tuple(
+        bh::make_pair(transition.parent(), resolveInitialState(transition)),
+        bh::make_pair(transition.parent(), transition.target()));
+};
+
 template <class State> constexpr auto collect_child_state_typeids_recursive(State parentState)
 {
     auto transitions = flatten_transition_table(parentState);
@@ -62,7 +69,6 @@ template <class State> constexpr auto collect_child_state_typeids_recursive(Stat
 template <class State> constexpr auto collect_child_states_recursive(State parentState)
 {
     return bh::flatten(bh::transform(flatten_transition_table(parentState), extractExtendedStates));
-    ;
 }
 
 template <class State> constexpr auto collect_state_typeids_recursive(State parentState)
@@ -90,4 +96,11 @@ template <class State> constexpr auto collect_child_states(State state)
     return remove_duplicates(
         bh::flatten(bh::transform(make_transition_table2(state), extractStates)));
 }
+
+template <class State> constexpr auto collect_state_parentstate_pairs_recursively(State rootState)
+{
+    return remove_duplicates(bh::prepend(
+        bh::flatten(bh::transform(flatten_transition_table(rootState), extractParentAndState)),
+        bh::make_pair(rootState, rootState)));
+}
 }
\ No newline at end of file
diff --git a/include/hsm/details/flatten_internal_transition_table.h b/include/hsm/details/flatten_internal_transition_table.h
index 7392c79..89e7b09 100644
--- a/include/hsm/details/flatten_internal_transition_table.h
+++ b/include/hsm/details/flatten_internal_transition_table.h
@@ -76,29 +76,57 @@ constexpr auto extend_internal_transition(Transition internalTransition, States
 }
 
 /**
- * Returns the internal transitions for each for each state
+ * Extends an internal transitions to all provided states
+ *
+ * @param internalTranstion Internal transition that should be extended
+ * @param states tuple of states
+ */
+template <class Transition, class ParentState, class State>
+constexpr auto
+extend_internal_transition2(Transition internalTransition, ParentState parent, State state)
+{
+    return bh::make_basic_tuple(details::internal_extended_transition(
+        parent,
+        details::transition(
+            state,
+            internalTransition.event(),
+            internalTransition.guard(),
+            internalTransition.action(),
+            state)));
+}
+
+/**
+ * Returns the internal transitions for each state
  * [[transition1, transition2], [transition3, transition4], []]
  *
  * @param states a tuple of states
  */
-constexpr auto get_internal_transitions = [](auto states) {
+constexpr auto get_internal_transitions = [](auto stateAndParentStatePairs) {
     return bh::flatten(bh::filter(
         bh::transform(
-            states,
-            [](auto parentState) {
-                constexpr auto extend
-                    = bh::capture(parentState)([](auto parentState, auto transition) {
-                          // Folowing lines satisfies older gcc -Werror=unused-but-set-parameter
-                          (void)transition;
-                          if constexpr (has_transition_table(parentState)) {
-                              return extend_internal_transition(
-                                  transition, collect_child_states(parentState));
-                          } else {
-                              return bh::make_basic_tuple();
-                          }
-                      });
+            stateAndParentStatePairs,
+            [](auto stateAndParentStatePair) {
+                constexpr auto extend = bh::capture(stateAndParentStatePair)(
+                    [](auto stateAndParentStatePair, auto internalTransition) {
+                        // Folowing lines satisfies older gcc -Werror=unused-but-set-parameter
+                        (void)internalTransition;
+                        if constexpr (has_transition_table(bh::second(stateAndParentStatePair))) {
+                            return extend_internal_transition(
+                                internalTransition,
+                                collect_child_states(bh::second(stateAndParentStatePair)));
+                        } else if constexpr (has_internal_transition_table(
+                                                 bh::second(stateAndParentStatePair))) {
+                            return extend_internal_transition2(
+                                internalTransition,
+                                bh::first(stateAndParentStatePair),
+                                bh::second(stateAndParentStatePair));
+                        } else {
+                            return bh::make_basic_tuple();
+                        }
+                    });
 
-                return bh::transform(get_internal_transition_table(parentState), extend);
+                return bh::transform(
+                    get_internal_transition_table(bh::second(stateAndParentStatePair)), extend);
             }),
         isNotEmpty));
 };
@@ -110,9 +138,10 @@ constexpr auto get_internal_transitions = [](auto states) {
  */
 template <class State> constexpr auto flatten_internal_transition_table(State rootState)
 {
-    return [](auto states) {
-        return bh::to<bh::basic_tuple_tag>(bh::flatten(get_internal_transitions(states)));
-    }(collect_states_recursive(rootState));
+    return [](auto stateAndParentStatePairs) {
+        return remove_duplicate_types(bh::to<bh::basic_tuple_tag>(
+            bh::flatten(get_internal_transitions(stateAndParentStatePairs))));
+    }(collect_state_parentstate_pairs_recursively(rootState));
 }
 
 } // namespace hsm
\ No newline at end of file
diff --git a/include/hsm/details/flatten_transition_table.h b/include/hsm/details/flatten_transition_table.h
index bf16e0e..920eae5 100644
--- a/include/hsm/details/flatten_transition_table.h
+++ b/include/hsm/details/flatten_transition_table.h
@@ -23,6 +23,12 @@ template <class State> constexpr auto flatten_sub_transition_table(State state);
 
 }
 
+/**
+ * This function iterates recursively trough the transition table of a state provided by
+ * `make_transition_table()` and collects all transitions.
+ *
+ * @return a list of ExtendedTransition
+ */
 template <class State> constexpr auto flatten_transition_table(State state)
 {
     auto flattenSubTransitionTable = [state](auto transition) {
diff --git a/test/integration/internal_transition.cpp b/test/integration/internal_transition.cpp
index cdc6d03..f931554 100644
--- a/test/integration/internal_transition.cpp
+++ b/test/integration/internal_transition.cpp
@@ -60,6 +60,8 @@ struct e8 {
 };
 struct e9 {
 };
+struct e10 { };
+struct e11 { };
 
 // Guards
 const auto fail = [](auto /*event*/, auto /*source*/, auto /*target*/) { return false; };
@@ -94,15 +96,27 @@ struct SubState {
     }
 };
 
+struct InternalOnlySubState {
+    static constexpr auto make_internal_transition_table()
+    {
+        // clang-format off
+        return hsm::transition_table(
+            + (hsm::event<e11>)
+        );
+        // clang-format on
+    }
+};
+
 struct MainState {
     static constexpr auto make_transition_table()
     {
         // clang-format off
         return hsm::transition_table(
-            * hsm::state<S1> + hsm::event<e1> = hsm::state<S2>
-            , hsm::state<S1> + hsm::event<e7> = hsm::state<S2>
-            , hsm::state<S1> + hsm::event<e3> = hsm::state<SubState>
-            , hsm::state<S2> + hsm::event<e6> = hsm::state<S1>
+            * hsm::state<S1> + hsm::event<e1>  = hsm::state<S2>
+            , hsm::state<S1> + hsm::event<e7>  = hsm::state<S2>
+            , hsm::state<S1> + hsm::event<e3>  = hsm::state<SubState>
+            , hsm::state<S2> + hsm::event<e6>  = hsm::state<S1>
+            , hsm::state<S1> + hsm::event<e10> = hsm::state<InternalOnlySubState> 
         );
         // clang-format on
     }
@@ -214,3 +228,12 @@ TEST_F(InternalTransitionTests, should_not_transit_to_initial_state)
     sm.process_event(e1 {});
     ASSERT_TRUE(sm.is(hsm::state<S2>));
 }
+
+TEST_F(InternalTransitionTests, should_recognize_substates_with_only_internal_transition_table)
+{
+    ASSERT_TRUE(sm.is(hsm::state<S1>));
+    sm.process_event(e10 {});
+    ASSERT_TRUE(sm.is(hsm::state<InternalOnlySubState>));
+    sm.process_event(e11 {});
+    ASSERT_TRUE(sm.is(hsm::state<InternalOnlySubState>));
+}
\ No newline at end of file
diff --git a/test/unit/collect_events_tests.cpp b/test/unit/collect_events_tests.cpp
index f46aac3..5538636 100644
--- a/test/unit/collect_events_tests.cpp
+++ b/test/unit/collect_events_tests.cpp
@@ -62,7 +62,7 @@ TEST_F(CollectEventsTests, should_collect_event_typeids_recursive)
 {
     auto collectedEvents = hsm::collect_event_typeids_recursive(hsm::state_t<S> {});
     auto expectedEvents = bh::make_basic_tuple(
-        bh::typeid_(E1 {}), bh::typeid_(E2 {}), bh::typeid_(E4 {}), bh::typeid_(E3 {}));
+        bh::typeid_(E1 {}), bh::typeid_(E2 {}), bh::typeid_(E3 {}), bh::typeid_(E4 {}));
 
     ASSERT_EQ(bh::size(expectedEvents), bh::size(collectedEvents));
     ASSERT_TRUE(bh::equal(expectedEvents, collectedEvents));
@@ -73,7 +73,7 @@ TEST_F(CollectEventsTests, should_collect_events_recursive)
     auto collectedEvents
         = bh::transform(hsm::collect_events_recursive(hsm::state_t<S> {}), bh::typeid_);
     auto expectedEvents = bh::make_basic_tuple(
-        bh::typeid_(E1 {}), bh::typeid_(E2 {}), bh::typeid_(E4 {}), bh::typeid_(E3 {}));
+        bh::typeid_(E1 {}), bh::typeid_(E2 {}), bh::typeid_(E3 {}), bh::typeid_(E4 {}));
 
     ASSERT_EQ(bh::size(expectedEvents), bh::size(collectedEvents));
     ASSERT_TRUE(bh::equal(expectedEvents, collectedEvents));
diff --git a/test/unit/collect_states_tests.cpp b/test/unit/collect_states_tests.cpp
index dabe3bb..5fd6e63 100644
--- a/test/unit/collect_states_tests.cpp
+++ b/test/unit/collect_states_tests.cpp
@@ -8,6 +8,7 @@
 #include <gtest/gtest.h>
 
 #include <boost/hana.hpp>
+#include <boost/hana/experimental/printable.hpp>
 
 using namespace ::testing;
 
@@ -300,4 +301,33 @@ TEST_F(CollectStatesTests, should_collect_parent_state_typeids)
         bh::typeid_);
 
     ASSERT_EQ(expectedParentStates, collectedParentStates);
+}
+
+TEST_F(CollectStatesTests, should_collect_parent_state_and_state_typeids)
+{
+    auto collectedParentStatesAndStatesTypesids
+        = hsm::collect_state_parentstate_pairs_recursively(hsm::state_t<MainState> {});
+
+    ASSERT_EQ(bh::size_c<11>, bh::size(collectedParentStatesAndStatesTypesids));
+
+    auto expected = bh::make_tuple(
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::state_t<MainState> {}),
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::state_t<S1> {}),
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::state_t<S2> {}),
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::state_t<SubState> {}),
+        bh::make_pair(hsm::state_t<SubState> {}, hsm::state_t<S1> {}),
+        bh::make_pair(hsm::state_t<SubState> {}, hsm::state_t<S2> {}),
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::history_t<HistorySubState> {}),
+        bh::make_pair(hsm::state_t<HistorySubState> {}, hsm::state_t<S1> {}),
+        bh::make_pair(hsm::state_t<HistorySubState> {}, hsm::state_t<S2> {}),
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::state_t<S3> {}),
+        bh::make_pair(hsm::state_t<MainState> {}, hsm::state_t<S4> {}));
+
+    auto toTypes = [](auto pairs) {
+        return bh::transform(pairs, [](auto pair) {
+            return bh::make_pair(bh::typeid_(bh::first(pair)), bh::typeid_(bh::second(pair)));
+        });
+    };
+
+    ASSERT_EQ(toTypes(expected), toTypes(collectedParentStatesAndStatesTypesids));
 }
\ No newline at end of file
diff --git a/test/unit/flatten_internal_transition_table_tests.cpp b/test/unit/flatten_internal_transition_table_tests.cpp
index c7bf83e..92cb48f 100644
--- a/test/unit/flatten_internal_transition_table_tests.cpp
+++ b/test/unit/flatten_internal_transition_table_tests.cpp
@@ -6,24 +6,39 @@
 #include <gtest/gtest.h>
 
 #include <boost/hana.hpp>
+#include <boost/hana/experimental/printable.hpp>
 
 using namespace ::testing;
 using namespace hsm;
 
 namespace {
 
-struct T {
+struct PlainState { };
+
+struct InternalOnly {
     static constexpr auto make_internal_transition_table()
     {
         return hsm::transition_table(hsm::internal_transition("event", "guard", "action"));
     }
 };
 
-struct P {
+struct X {
+    static constexpr auto make_transition_table()
+    {
+        return hsm::transition_table(hsm::transition(
+            hsm::state_t<InternalOnly> {},
+            "event",
+            "guard",
+            "action",
+            hsm::state_t<InternalOnly> {}));
+    }
+};
+
+struct Y {
     static constexpr auto make_transition_table()
     {
-        return hsm::transition_table(
-            hsm::transition(hsm::state_t<T> {}, "event", "guard", "action", hsm::state_t<T> {}));
+        return hsm::transition_table(hsm::transition(
+            hsm::state_t<PlainState> {}, "event", "guard", "action", hsm::state_t<PlainState> {}));
     }
 
     static constexpr auto make_internal_transition_table()
@@ -32,11 +47,28 @@ struct P {
     }
 };
 
-struct S {
+struct Z {
     static constexpr auto make_transition_table()
     {
-        return hsm::transition_table(
-            hsm::transition(hsm::state_t<T> {}, "event", "guard", "action", hsm::state_t<P> {}));
+        return hsm::transition_table(hsm::transition(
+            hsm::state_t<InternalOnly> {},
+            "event",
+            "guard",
+            "action",
+            hsm::state_t<InternalOnly> {}));
+    }
+
+    static constexpr auto make_internal_transition_table()
+    {
+        return hsm::transition_table(hsm::internal_transition("event", "guard", "action"));
+    }
+};
+
+struct P {
+    static constexpr auto make_transition_table()
+    {
+        return hsm::transition_table(hsm::transition(
+            hsm::state_t<InternalOnly> {}, "event", "guard", "action", hsm::state_t<Z> {}));
     }
 
     static constexpr auto make_internal_transition_table()
@@ -49,32 +81,55 @@ class FlattenInternalTransitionTableTests : public Test {
 };
 }
 
-TEST_F(FlattenInternalTransitionTableTests, should_flatten_internal_transition_table)
+TEST_F(FlattenInternalTransitionTableTests, should_flatten_root_internal_transition_table)
 {
-    auto flattenInternalTransitionTable = flatten_internal_transition_table(hsm::state_t<S> {});
-
-    ASSERT_EQ(boost::hana::size_c<3>, boost::hana::size(flattenInternalTransitionTable));
+    auto flattenInternalTransitionTable = flatten_internal_transition_table(hsm::state_t<Y> {});
+    ASSERT_EQ(boost::hana::size_c<1>, boost::hana::size(flattenInternalTransitionTable));
 
-    // S{} State
     ASSERT_TRUE(
-        hsm::state_t<P> {} == boost::hana::at_c<0>(flattenInternalTransitionTable).parent());
+        hsm::state_t<Y> {} == boost::hana::at_c<0>(flattenInternalTransitionTable).parent());
     ASSERT_TRUE(
-        hsm::state_t<T> {} == boost::hana::at_c<0>(flattenInternalTransitionTable).source());
+        hsm::state_t<PlainState> {}
+        == boost::hana::at_c<0>(flattenInternalTransitionTable).source());
     ASSERT_TRUE(
-        hsm::state_t<T> {} == boost::hana::at_c<0>(flattenInternalTransitionTable).target());
+        hsm::state_t<PlainState> {}
+        == boost::hana::at_c<0>(flattenInternalTransitionTable).target());
+}
+
+TEST_F(FlattenInternalTransitionTableTests, should_flatten_substate_internal_transition_table)
+{
+    auto flattenInternalTransitionTable = flatten_internal_transition_table(hsm::state_t<X> {});
+    ASSERT_EQ(boost::hana::size_c<1>, boost::hana::size(flattenInternalTransitionTable));
 
     ASSERT_TRUE(
-        hsm::state_t<S> {} == boost::hana::at_c<1>(flattenInternalTransitionTable).parent());
+        hsm::state_t<X> {} == boost::hana::at_c<0>(flattenInternalTransitionTable).parent());
     ASSERT_TRUE(
-        hsm::state_t<T> {} == boost::hana::at_c<1>(flattenInternalTransitionTable).source());
+        hsm::state_t<InternalOnly> {}
+        == boost::hana::at_c<0>(flattenInternalTransitionTable).source());
     ASSERT_TRUE(
-        hsm::state_t<T> {} == boost::hana::at_c<1>(flattenInternalTransitionTable).target());
+        hsm::state_t<InternalOnly> {}
+        == boost::hana::at_c<0>(flattenInternalTransitionTable).target());
+}
+
+TEST_F(
+    FlattenInternalTransitionTableTests, should_flatten_root_and_substate_internal_transition_table)
+{
+    auto flattenInternalTransitionTable = flatten_internal_transition_table(hsm::state_t<Z> {});
+    ASSERT_EQ(boost::hana::size_c<1>, boost::hana::size(flattenInternalTransitionTable));
 
-    // P{} State
     ASSERT_TRUE(
-        hsm::state_t<S> {} == boost::hana::at_c<2>(flattenInternalTransitionTable).parent());
+        hsm::state_t<Z> {} == boost::hana::at_c<0>(flattenInternalTransitionTable).parent());
     ASSERT_TRUE(
-        hsm::state_t<P> {} == boost::hana::at_c<2>(flattenInternalTransitionTable).source());
+        hsm::state_t<InternalOnly> {}
+        == boost::hana::at_c<0>(flattenInternalTransitionTable).source());
     ASSERT_TRUE(
-        hsm::state_t<P> {} == boost::hana::at_c<2>(flattenInternalTransitionTable).target());
+        hsm::state_t<InternalOnly> {}
+        == boost::hana::at_c<0>(flattenInternalTransitionTable).target());
+}
+
+TEST_F(FlattenInternalTransitionTableTests, should_flaten_internal_transition_table)
+{
+    auto flattenInternalTransitionTable = flatten_internal_transition_table(hsm::state_t<P> {});
+
+    ASSERT_EQ(boost::hana::size_c<3>, boost::hana::size(flattenInternalTransitionTable));
 }
\ No newline at end of file