Well, the Hijri date 11 Rabi Al Thani 1411 corresponds to the Gregorian date Monday, 29 October 1990. This date lies in the fourth month of the Hijri year 1411 AH, which is Rabi Al-Thani of 1411 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1411/04/11 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 29 October 1990 to its equivalent Arabic date.
The following is the conversion of the Arabic date 11 Rabi Al Thani 1411 AH to its equivalent Gregorian date.
فَإِذَا نَزَلَ بِسَاحَتِهِمْ فَسَآءَ صَبَاحُ ٱلْمُنذَرِينَ
But when it cometh home to them, then it will be a hapless morn for those who have been warned.
Surah As-Saaffaat(37:177)