Index: src/pmc/boolean.pmc
===================================================================
--- src/pmc/boolean.pmc	(revision 48997)
+++ src/pmc/boolean.pmc	(working copy)
@@ -184,6 +184,29 @@
         SELF.set_bool(VTABLE_shift_integer(INTERP, info));
     }
 
+/*
+
+=item C<INTVAL isa(STRING *name)>
+
+Temporary solution for backward compatibility until deprecation cycle.
+
+See TT #1790
+
+=cut
+
+*/
+
+    VTABLE INTVAL isa(STRING *some)
+    {
+        if (Parrot_str_equal(INTERP, some, CONST_STRING(INTERP, "Boolean")))
+            return 1;
+        if (Parrot_str_equal(INTERP, some, CONST_STRING(INTERP, "scalar")))
+            return 1;
+        if (Parrot_str_equal(INTERP, some, CONST_STRING(INTERP, "Integer")))
+            return 1;
+        return 0;
+    }
+
 }
 
 /*
Index: t/pmc/boolean.t
===================================================================
--- t/pmc/boolean.t	(revision 48997)
+++ t/pmc/boolean.t	(working copy)
@@ -19,7 +19,7 @@
 
 .sub main :main
     .include 'test_more.pir'
-    plan(31)
+    plan(32)
     init_null_tests()
     init_int_tests()
     instantiate_tests()
@@ -207,6 +207,10 @@
     .local int b
 
     p = new ['Boolean']
+
+    isa b, p, "Integer"
+    is(b, 1, "Boolean isa Integer - going to be deprecated - TT #1790")
+
     does b, p, "scalar"
     is(b, 1, "Boolean does scalar")
     does b, p, "boolean"