Well, the Hijri date 15 Rajab 1266 corresponds to the Gregorian date Sunday, 26 May 1850. This date lies in the seventh month of the Hijri year 1266 AH, which is Rajab of 1266 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1266/07/15 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 26 May 1850 to its equivalent Arabic date.
The following is the conversion of the Arabic date 15 Rajab 1266 AH to its equivalent Gregorian date.
أَوَلَا يَعْلَمُونَ أَنَّ ٱللَّهَ يَعْلَمُ مَا يُسِرُّونَ وَمَا يُعْلِنُونَ
Are they then unaware that Allah knoweth that which they keep hidden and that which they proclaim?
Surah Al-Baqara(2:77)