Well, the Hijri date 1 Rabi Al Awwal 1256 corresponds to the Gregorian date Saturday, 2 May 1840. This date lies in the third month of the Hijri year 1256 AH, which is Rabi Al-Awwal of 1256 AH. Both this Hijri and Gregorian date occur on the single day that is Saturday without any doubt. The Arabic date 1256/03/01 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 2 May 1840 to its equivalent Arabic date.
The following is the conversion of the Arabic date 1 Rabi Al Awwal 1256 AH to its equivalent Gregorian date.
وَأُحِيطَ بِثَمَرِهِۦ فَأَصْبَحَ يُقَلِّبُ كَفَّيْهِ عَلَىٰ مَآ أَنفَقَ فِيهَا وَهِىَ خَاوِيَةٌ عَلَىٰ عُرُوشِهَا وَيَقُولُ يَٰلَيْتَنِى لَمْ أُشْرِكْ بِرَبِّىٓ أَحَدًۭا
And his fruit was beset (with destruction). Then began he to wring his hands for all that he had spent upon it, when (now) it was all ruined on its trellises, and to say: Would that I had ascribed no partner to my Lord!
Surah Al-Kahf(18:42)