Well, the Hijri date 21 Shawwal 1255 corresponds to the Gregorian date Friday, 27 December 1839. This date lies in the tenth month of the Hijri year 1255 AH, which is Shawwal of 1255 AH. Both this Hijri and Gregorian date occur on the single day that is Friday without any doubt. The Arabic date 1255/10/21 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 27 December 1839 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Shawwal 1255 AH to its equivalent Gregorian date.
وَقُلِ ٱلْحَمْدُ لِلَّهِ ٱلَّذِى لَمْ يَتَّخِذْ وَلَدًۭا وَلَمْ يَكُن لَّهُۥ شَرِيكٌۭ فِى ٱلْمُلْكِ وَلَمْ يَكُن لَّهُۥ وَلِىٌّۭ مِّنَ ٱلذُّلِّ ۖ وَكَبِّرْهُ تَكْبِيرًۢا
And say: Praise be to Allah, Who hath not taken unto Himself a son, and Who hath no partner in the Sovereignty, nor hath He any protecting friend through dependence. And magnify Him with all magnificence.
Surah Al-Israa(17:111)