Well, the Hijri date 29 Rajab 1221 corresponds to the Gregorian date Saturday, 11 October 1806. This date lies in the seventh month of the Hijri year 1221 AH, which is Rajab of 1221 AH. Both this Hijri and Gregorian date occur on the single day that is Saturday without any doubt. The Arabic date 1221/07/29 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 11 October 1806 to its equivalent Arabic date.
The following is the conversion of the Arabic date 29 Rajab 1221 AH to its equivalent Gregorian date.
إِنَّمَا يَعْمُرُ مَسَٰجِدَ ٱللَّهِ مَنْ ءَامَنَ بِٱللَّهِ وَٱلْيَوْمِ ٱلْءَاخِرِ وَأَقَامَ ٱلصَّلَوٰةَ وَءَاتَى ٱلزَّكَوٰةَ وَلَمْ يَخْشَ إِلَّا ٱللَّهَ ۖ فَعَسَىٰٓ أُو۟لَٰٓئِكَ أَن يَكُونُوا۟ مِنَ ٱلْمُهْتَدِينَ
He only shall tend Allah's sanctuaries who believeth in Allah and the Last Day and observeth proper worship and payeth the poor-due and feareth none save Allah. For such (only) is it possible that they can be of the rightly guided.
Surah At-Tawba(9:18)