Well, the Hijri date 29 Safar 1277 corresponds to the Gregorian date Saturday, 15 September 1860. This date lies in the second month of the Hijri year 1277 AH, which is Safar of 1277 AH. Both this Hijri and Gregorian date occur on the single day that is Saturday without any doubt. The Arabic date 1277/02/29 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 15 September 1860 to its equivalent Arabic date.
The following is the conversion of the Arabic date 29 Safar 1277 AH to its equivalent Gregorian date.
لَا يُؤْمِنُونَ بِهِۦ حَتَّىٰ يَرَوُا۟ ٱلْعَذَابَ ٱلْأَلِيمَ
They will not believe in it till they behold the painful doom,
Surah Ash-Shu'araa(26:201)