diff --git a/src/pythonize.cpp b/src/pythonize.cpp
index d8fb038..9d41f69 100644
--- a/src/pythonize.cpp
+++ b/src/pythonize.cpp
@@ -42,8 +42,12 @@ Pythonize::Pythonize ()
 
     if (!Py_IsInitialized ())
     {
-        PyEval_InitThreads ();
-        Py_Initialize ();
+        Py_Initialize();
+
+#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION <= 6
+        // initialize thread support
+        PyEval_InitThreads();
+#endif
         if (!Py_IsInitialized ())
         {
             pythonInit = 0;
@@ -51,9 +55,6 @@ Pythonize::Pythonize ()
         }
 
         if (debug) printf ("Python interpreter initialized!\n\n");
-
-        // free the lock
-        PyEval_ReleaseLock();
     }
 }