Well, the Hijri date 21 Dhul Qidah 1236 corresponds to the Gregorian date Sunday, 19 August 1821. This date lies in the eleventh month of the Hijri year 1236 AH, which is Dhu Al-Qidah of 1236 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1236/11/21 is calculated using the Umm Al-Qura calendar and the sighting of the moon. One thing to remember is that this Arabic date may occur on different Gregorian date depending upon the region and country and obviously the moon.
If you are still not sure about the date then you can use our Arabic date converter.
The following is the conversion of the Gregorian date 19 August 1821 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Dhul Qidah 1236 AH to its equivalent Gregorian date.
فَقَدْ كَذَّبُوا۟ فَسَيَأْتِيهِمْ أَنۢبَٰٓؤُا۟ مَا كَانُوا۟ بِهِۦ يَسْتَهْزِءُونَ
Now they have denied (the Truth); but there will come unto them tidings of that whereat they used to scoff.
Surah Ash-Shu'araa(26:6)