diff --git a/src/code/time.lisp b/src/code/time.lisp
index 51457f5179f616d4cdbddb6e184cdca7462e48e3..bf853a2b6a4d6cebb2e541931797a7346a6f36ea 100644
--- a/src/code/time.lisp
+++ b/src/code/time.lisp
@@ -223,8 +223,11 @@
 	   (type (mod 24) hour)
 	   (type (integer 1 31) date)
 	   (type (integer 1 12) month)
-	   (type (or (integer 0 99) (integer 1900)) year)
-	   (type (or null rational) time-zone))
+	   ;; 1899 to account for time zones that are equivalent to 1900.
+	   (type (or (integer 0 99) (integer 1899)) year)
+	   (type (or null rational) time-zone)
+	   ;; Result must be non-negative integer!
+	   (values (integer 0)))
   (let* ((year (if (< year 100)
 		   (pick-obvious-year year)
 		   year))