Well, the Hijri date 6 Rabi Al Thani 1391 corresponds to the Gregorian date Sunday, 30 May 1971. This date lies in the fourth month of the Hijri year 1391 AH, which is Rabi Al-Thani of 1391 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1391/04/06 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 30 May 1971 to its equivalent Arabic date.
The following is the conversion of the Arabic date 6 Rabi Al Thani 1391 AH to its equivalent Gregorian date.
وَكَأَيِّن مِّن قَرْيَةٍ أَمْلَيْتُ لَهَا وَهِىَ ظَالِمَةٌۭ ثُمَّ أَخَذْتُهَا وَإِلَىَّ ٱلْمَصِيرُ
And how many a township did I suffer long though it was sinful! Then I grasped it. Unto Me is the return.
Surah Al-Hajj(22:48)