Well, the Hijri date 21 Shawwal 1376 corresponds to the Gregorian date Monday, 20 May 1957. This date lies in the tenth month of the Hijri year 1376 AH, which is Shawwal of 1376 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1376/10/21 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 20 May 1957 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Shawwal 1376 AH to its equivalent Gregorian date.
لَٰكِنِ ٱلرَّسُولُ وَٱلَّذِينَ ءَامَنُوا۟ مَعَهُۥ جَٰهَدُوا۟ بِأَمْوَٰلِهِمْ وَأَنفُسِهِمْ ۚ وَأُو۟لَٰٓئِكَ لَهُمُ ٱلْخَيْرَٰتُ ۖ وَأُو۟لَٰٓئِكَ هُمُ ٱلْمُفْلِحُونَ
But the messenger and those who believe with him strive with their wealth and their lives. Such are they for whom are the good things. Such are they who are the successful.
Surah At-Tawba(9:88)