Well, the Hijri date 21 Rajab 1300 corresponds to the Gregorian date Sunday, 27 May 1883. This date lies in the seventh month of the Hijri year 1300 AH, which is Rajab of 1300 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1300/07/21 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 27 May 1883 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Rajab 1300 AH to its equivalent Gregorian date.
وَمَا كُنتَ تَتْلُوا۟ مِن قَبْلِهِۦ مِن كِتَٰبٍۢ وَلَا تَخُطُّهُۥ بِيَمِينِكَ ۖ إِذًۭا لَّٱرْتَابَ ٱلْمُبْطِلُونَ
And thou (O Muhammad) wast not a reader of any scripture before it, nor didst thou write it with thy right hand, for then might those have doubted, who follow falsehood.
Surah Al-Ankaboot(29:48)