diff --git a/README.md b/README.md
index 2f79737..400dec9 100644
--- a/README.md
+++ b/README.md
@@ -187,12 +187,13 @@ The field under this rule must be one of `'on'`, `'yes'`, `'1'`, `'true'` (the s
 
 The field under this rule must be a date after the given minimum.
 
-The parameter should be any valid string that can be parsed by `strtotime`. For example:
+The parameter should be any valid string that can be parsed by `strtotime` including unix timestamps. For example:
 
 * after:next week
 * after:2016-12-31
 * after:2016
 * after:2016-12-31 09:56:02
+* after:1583946133
 
 </details>
 
diff --git a/src/Rules/Behaviours/CanValidateDates.php b/src/Rules/Behaviours/CanValidateDates.php
index dc30378..900accf 100644
--- a/src/Rules/Behaviours/CanValidateDates.php
+++ b/src/Rules/Behaviours/CanValidateDates.php
@@ -6,20 +6,24 @@
 
 trait CanValidateDates
 {
-    protected function assertDate(string $date): void
+    protected function assertDate(int|string $date): void
     {
-        if (!$this->isValidDate($date)) {
+        if ($this->getTimeStamp($date) === null) {
             throw ParameterException::invalidDate($date);
         }
     }
 
-    protected function isValidDate(string $date): bool
+    protected function getTimeStamp(int|string $date): ?int
     {
-        return (strtotime($date) !== false);
-    }
+        if (is_int($date)) {
+            return $date;
+        }
 
-    protected function getTimeStamp($date): int
-    {
-        return strtotime($date);
+        if (is_string($date) && is_numeric($date)) {
+            return (int)$date;
+        }
+
+        $timestamp = strtotime($date);
+        return $timestamp !== false ? $timestamp : null;
     }
 }
diff --git a/tests/Rules/AfterTest.php b/tests/Rules/AfterTest.php
index 1232a95..37985ea 100644
--- a/tests/Rules/AfterTest.php
+++ b/tests/Rules/AfterTest.php
@@ -58,7 +58,8 @@ public static function getInvalidDates(): array
             [$now->format("Y m d")],
             [$now->format("Y m d h:i:s")],
             ["tommorow"], //typo
-            ["lasst year"] //typo
+            ["lasst year"], //typo
+            ["0123"] //invalid unix
         ];
     }
 
@@ -72,7 +73,8 @@ public static function getValidDates(): array
             [$now->format("Y-m-d h:i:s")],
             ["now"],
             ["tomorrow"],
-            ["2 years ago"]
+            ["2 years ago"],
+            ["1741716133"]
         ];
     }
 
diff --git a/tests/Rules/BeforeTest.php b/tests/Rules/BeforeTest.php
index b34bc6a..58e193a 100644
--- a/tests/Rules/BeforeTest.php
+++ b/tests/Rules/BeforeTest.php
@@ -40,7 +40,8 @@ public static function getValidDates(): array
             [$now->format("Y-m-d h:i:s")],
             ["now"],
             ["tomorrow"],
-            ["2 years ago"]
+            ["2 years ago"],
+            ["1741716133"]
         ];
     }
 
@@ -64,7 +65,8 @@ public static function getInvalidDates(): array
             [$now->format("Y m d")],
             [$now->format("Y m d h:i:s")],
             ["tommorow"], //typo
-            ["lasst year"] //typo
+            ["lasst year"], //typo
+            ["0123"] //invalid unix
         ];
     }