diff --git a/source/Ox/js/Date.js b/source/Ox/js/Date.js
index 0eff3148..74668b2e 100644
--- a/source/Ox/js/Date.js
+++ b/source/Ox/js/Date.js
@@ -257,7 +257,7 @@ Ox.makeDate <f> Takes a date, number or string, returns a date
 @*/
 Ox.makeDate = function(date) {
     // Safari 4/5 (<= 534.59.10) doesn't parse YYYY, YYYY-MM or YYYY-MM-DD
-    if (Ox.isString(date)) {
+    if (Ox.isString(date) && Ox.isInvalidDate(new Date(date))) {
         if (/^\d{4}$/.test(date)) {
             date += '-01-01';
         } else if (/^\d{4}-\d{2}$/.test(date)) {
diff --git a/source/Ox/js/Type.js b/source/Ox/js/Type.js
index 03aded5e..1bc09f73 100644
--- a/source/Ox/js/Type.js
+++ b/source/Ox/js/Type.js
@@ -241,6 +241,17 @@ Ox.isInt = function(value) {
     return isFinite(value) && value === Math.floor(value);
 };
 
+/*
+Ox.isInvalidDate <f> Tests if a value is an invalid date
+    (value) -> <b> True if the value is an invalid date
+    value <*> Any value
+    > Ox.isInvalidDate(new Date('foo'))
+    true
+*/
+Ox.isValidDate = function(value) {
+    return Ox.isDate(value) && Ox.isNaN(value.getTime());
+};
+
 /*@
 Ox.isNaN <f> Tests if a value is `NaN`
     (value) -> <b> True if the value is `NaN`
@@ -371,6 +382,17 @@ Ox.isUndefined = function(value) {
     return Ox.typeOf(value) == 'undefined';
 };
 
+/*
+Ox.isValidDate <f> Tests if a value is a valid date
+    (value) -> <b> True if the value is a valid date
+    value <*> Any value
+    > Ox.isValidDate(new Date())
+    true
+*/
+Ox.isValidDate = function(value) {
+    return Ox.isDate(value) && !Ox.isNaN(value.getTime());
+};
+
 /*@
 Ox.typeOf <f> Returns the type of a value
     (value) -> <s> Type