Well, the Hijri date 26 Muharram 1511 corresponds to the Gregorian date Monday, 25 August 2087. This date lies in the first month of the Hijri year 1511 AH, which is Muharram of 1511 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1511/01/26 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 25 August 2087 to its equivalent Arabic date.
The following is the conversion of the Arabic date 26 Muharram 1511 AH to its equivalent Gregorian date.
فَلَا تَكُ فِى مِرْيَةٍۢ مِّمَّا يَعْبُدُ هَٰٓؤُلَآءِ ۚ مَا يَعْبُدُونَ إِلَّا كَمَا يَعْبُدُ ءَابَآؤُهُم مِّن قَبْلُ ۚ وَإِنَّا لَمُوَفُّوهُمْ نَصِيبَهُمْ غَيْرَ مَنقُوصٍۢ
So be not thou in doubt concerning that which these (folk) worship. They worship only as their fathers worshipped aforetime. Lo! we shall pay them their whole due unabated.
Surah Hud(11:109)