Well, the Hijri date 21 Jumada Al Akhira 1366 corresponds to the Gregorian date Monday, 12 May 1947. This date lies in the sixth month of the Hijri year 1366 AH, which is Jumada Al-Thani of 1366 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1366/06/21 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 12 May 1947 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Jumada Al Akhira 1366 AH to its equivalent Gregorian date.
وَرَسُولًا إِلَىٰ بَنِىٓ إِسْرَٰٓءِيلَ أَنِّى قَدْ جِئْتُكُم بِـَٔايَةٍۢ مِّن رَّبِّكُمْ ۖ أَنِّىٓ أَخْلُقُ لَكُم مِّنَ ٱلطِّينِ كَهَيْـَٔةِ ٱلطَّيْرِ فَأَنفُخُ فِيهِ فَيَكُونُ طَيْرًۢا بِإِذْنِ ٱللَّهِ ۖ وَأُبْرِئُ ٱلْأَكْمَهَ وَٱلْأَبْرَصَ وَأُحْىِ ٱلْمَوْتَىٰ بِإِذْنِ ٱللَّهِ ۖ وَأُنَبِّئُكُم بِمَا تَأْكُلُونَ وَمَا تَدَّخِرُونَ فِى بُيُوتِكُمْ ۚ إِنَّ فِى ذَٰلِكَ لَءَايَةًۭ لَّكُمْ إِن كُنتُم مُّؤْمِنِينَ
And will make him a messenger unto the Children of Israel, (saying): Lo! I come unto you with a sign from your Lord. Lo! I fashion for you out of clay the likeness of a bird, and I breathe into it and it is a bird, by Allah's leave. I heal him who was born blind, and the leper, and I raise the dead, by Allah's leave. And I announce unto you what ye eat and what ye store up in your houses. Lo! herein verily is a portent for you, if ye are to be believers.
Surah Aal-i-Imraan(3:49)