diff --git a/src/kernel/save.c b/src/kernel/save.c
index 26b7a12ab..9dc0030e0 100644
--- a/src/kernel/save.c
+++ b/src/kernel/save.c
@@ -1076,7 +1076,8 @@ void write_faction(gamedata *data, const faction * f)
     ursprung *ur;
 
     assert(f->_alive);
-    write_faction_reference(f, data->store);
+    assert(f->no > 0 && f->no <= MAX_UNIT_NR);
+    WRITE_INT(data->store, f->no);
     WRITE_INT(data->store, f->subscription);
 #if RELEASE_VERSION >= SPELL_LEVEL_VERSION
     WRITE_INT(data->store, f->max_spelllevel);
diff --git a/src/renumber.c b/src/renumber.c
index ec9d61c66..1319eaa5f 100644
--- a/src/renumber.c
+++ b/src/renumber.c
@@ -88,11 +88,15 @@ int renumber_cmd(unit * u, order * ord)
         s = gettoken(token, sizeof(token));
         if (s && *s) {
             int id = atoi36((const char *)s);
-            attrib *a = a_find(f->attribs, &at_number);
-            if (!a)
-                a = a_add(&f->attribs, a_new(&at_number));
-            a->data.i = id;
+            if (id > 0 && id <= MAX_UNIT_NR) {
+                attrib *a = a_find(f->attribs, &at_number);
+                if (!a)
+                    a = a_add(&f->attribs, a_new(&at_number));
+                a->data.i = id;
+                break;
+            }
         }
+        cmistake(u, ord, 114, MSG_EVENT);
         break;
 
     case P_UNIT:
diff --git a/src/renumber.test.c b/src/renumber.test.c
index dfac52e8c..11fb022aa 100644
--- a/src/renumber.test.c
+++ b/src/renumber.test.c
@@ -51,6 +51,37 @@ static void test_renumber_faction_duplicate(CuTest *tc) {
     test_teardown();
 }
 
+static void test_renumber_faction_invalid(CuTest *tc) {
+    unit *u;
+    faction *f;
+    int no;
+    const struct locale *lang;
+
+    test_setup_ex(tc);
+    u = test_create_unit(f = test_create_faction(0), test_create_region(0, 0, 0));
+    no = f->no;
+    lang = f->locale;
+    u->thisorder = create_order(K_NUMBER, lang, "%s [halima]", LOC(lang, parameters[P_FACTION]));
+    renumber_cmd(u, u->thisorder);
+    CuAssertPtrNotNull(tc, test_find_messagetype(f->msgs, "error114"));
+    renumber_factions();
+    CuAssertIntEquals(tc, no, f->no);
+
+    test_clear_messages(f);
+    free_order(u->thisorder);
+    u->thisorder = create_order(K_NUMBER, lang, "%s 10000", LOC(lang, parameters[P_FACTION]));
+    renumber_cmd(u, u->thisorder);
+    CuAssertPtrNotNull(tc, test_find_messagetype(f->msgs, "error114"));
+
+    test_clear_messages(f);
+    free_order(u->thisorder);
+    u->thisorder = create_order(K_NUMBER, lang, "%s 0", LOC(lang, parameters[P_FACTION]));
+    renumber_cmd(u, u->thisorder);
+    CuAssertPtrNotNull(tc, test_find_messagetype(f->msgs, "error114"));
+
+    test_cleanup();
+}
+
 static void test_renumber_building(CuTest *tc) {
     unit *u;
     int uno, no;
@@ -232,5 +263,6 @@ CuSuite *get_renumber_suite(void)
     SUITE_ADD_TEST(suite, test_renumber_ship_duplicate);
     SUITE_ADD_TEST(suite, test_renumber_faction);
     SUITE_ADD_TEST(suite, test_renumber_faction_duplicate);
+    SUITE_ADD_TEST(suite, test_renumber_faction_invalid);
     return suite;
 }