diff --git a/src/Member.php b/src/Member.php
index 3c47658..435920e 100644
--- a/src/Member.php
+++ b/src/Member.php
@@ -26,7 +26,8 @@ class Member extends Model {
         'emailVertretungsberechtigter' => 'email_parents',
         'staatsangehoerigkeitId' => 'nationality_id',
         'konfessionId' => 'confession_id',
-        'geburtsDatum' => 'birthday'
+        'geburtsDatum' => 'birthday',
+        'eintrittsdatum' => 'joined_at',
     ];
 
     protected $guarded = [];
@@ -49,6 +50,10 @@ class Member extends Model {
         return Carbon::parse($this->attributes['birthday'])->format('Y-m-d');
     }
 
+    public function getJoinedAtAttribute() {
+        return Carbon::parse($this->attributes['joined_at'])->format('Y-m-d');
+    }
+
     public function getGenderIdAttribute() {
         return $this->attributes['gender_id'] == Gender::getNullValue() ? null : $this->attributes['gender_id'];
     }
diff --git a/tests/Unit/PullMemberTest.php b/tests/Unit/PullMemberTest.php
index 64fc708..19cee1b 100644
--- a/tests/Unit/PullMemberTest.php
+++ b/tests/Unit/PullMemberTest.php
@@ -33,7 +33,8 @@ class PullMemberTest extends TestCase
             'gender_id' => ['gender_id', [19, null]],
             'nationality_id' => ['nationality_id', [1054, null]],
             'confession_id' => ['confession_id', [1, null]],
-            'birthday' => ['birthday', ['1991-06-20', '1984-01-17']]
+            'birthday' => ['birthday', ['1991-06-20', '1984-01-17']],
+            'joined_at' => ['joined_at', ['2005-05-01', '2003-11-17']],
         ];
     }