diff --git a/lout/identity.cc b/lout/identity.cc
index 8953b3b..22af639 100644
--- a/lout/identity.cc
+++ b/lout/identity.cc
@@ -95,34 +95,5 @@ void IdentifiableObject::registerName (const char *className, const std::type_in
    currentlyConstructedClass = klass;
 }
 
-/**
- * \brief Returns, whether this class is an instance of the class, given by
- *    \em otherClassId, or of a sub class of this class.
- */
-bool IdentifiableObject::instanceOf_impl (std::intptr_t otherClassId)
-{
-   if (otherClassId == -1)
-      // Other class has not been registered yet, while it should have been,
-      // if this class is an instance of it or of a sub-class.
-      return false;
-
-   Class *otherClass = classesById.at (otherClassId);
-
-   if (otherClass == NULL) {
-      fprintf (stderr,
-               "WARNING: Something got wrong here, it seems that a "
-               "CLASS_ID was not initialized properly.\n");
-      return false;
-   }
-
-   for (Class *klass = classesById.at (classId); klass != NULL;
-        klass = klass->parent) {
-      if (klass == otherClass)
-         return true;
-   }
-
-   return false;
-}
-
 } // namespace identity
 } // namespace lout
diff --git a/lout/identity.hh b/lout/identity.hh
index b8a834f..6230ef1 100644
--- a/lout/identity.hh
+++ b/lout/identity.hh
@@ -136,20 +136,6 @@ public:
     *    registered.
     */
    const char *getClassName() { return classesById.at( classId )->className; }
-
-   template< typename T >
-   [[deprecated]]
-   inline bool
-   instanceOf()
-   {
-      const bool expected= dynamic_cast< T * >( this );
-      const bool witness= instanceOf_impl( T::CLASS_ID );
-      if( witness != expected ) throw std::logic_error{ "RTTI based `instanceOf` disagrees with Dillo's lout:: impl." };
-	  return expected;
-   }
-
-  private:
-   bool instanceOf_impl (std::intptr_t otherClassId);
 };
 
 } // namespace identity