Well, the Hijri date 12 Dhul Qidah 1240 corresponds to the Gregorian date Monday, 27 June 1825. This date lies in the eleventh month of the Hijri year 1240 AH, which is Dhu Al-Qidah of 1240 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1240/11/12 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 June 1825 to its equivalent Arabic date.
The following is the conversion of the Arabic date 12 Dhul Qidah 1240 AH to its equivalent Gregorian date.
وَجَدتُّهَا وَقَوْمَهَا يَسْجُدُونَ لِلشَّمْسِ مِن دُونِ ٱللَّهِ وَزَيَّنَ لَهُمُ ٱلشَّيْطَٰنُ أَعْمَٰلَهُمْ فَصَدَّهُمْ عَنِ ٱلسَّبِيلِ فَهُمْ لَا يَهْتَدُونَ
I found her and her people worshipping the sun instead of Allah; and Satan maketh their works fairseeming unto them, and debarreth them from the way (of Truth), so that they go not aright;
Surah An-Naml(27:24)