Well, the Hijri date 6 Muharram 1231 corresponds to the Gregorian date Thursday, 7 December 1815. This date lies in the first month of the Hijri year 1231 AH, which is Muharram of 1231 AH. Both this Hijri and Gregorian date occur on the single day that is Thursday without any doubt. The Arabic date 1231/01/06 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 7 December 1815 to its equivalent Arabic date.
The following is the conversion of the Arabic date 6 Muharram 1231 AH to its equivalent Gregorian date.
وَمِنْهُم مَّن يَقُولُ رَبَّنَآ ءَاتِنَا فِى ٱلدُّنْيَا حَسَنَةًۭ وَفِى ٱلْءَاخِرَةِ حَسَنَةًۭ وَقِنَا عَذَابَ ٱلنَّارِ
And of them (also) is he who saith: "Our Lord! Give unto us in the world that which is good and in the Hereafter that which is good, and guard us from the doom of Fire."
Surah Al-Baqara(2:201)