Well, the Hijri date 1 Rabi Al Thani 1420 corresponds to the Gregorian date Wednesday, 14 July 1999. This date lies in the fourth month of the Hijri year 1420 AH, which is Rabi Al-Thani of 1420 AH. Both this Hijri and Gregorian date occur on the single day that is Wednesday without any doubt. The Arabic date 1420/04/01 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 14 July 1999 to its equivalent Arabic date.
The following is the conversion of the Arabic date 1 Rabi Al Thani 1420 AH to its equivalent Gregorian date.
وَأَقْبَلَ بَعْضُهُمْ عَلَىٰ بَعْضٍۢ يَتَسَآءَلُونَ
And some of them draw near unto others, mutually questioning.
Surah As-Saaffaat(37:27)
Sahih al-Bukhari
Merits of the Helpers in Madinah (Ansaar)
Chapter: The emigration to Ethiopia
Narrated Abu Musa:
We received the news of the departure of the Prophet (to Medina) while we were in Yemen. So we went on board a ship but our ship took us away to An-Najashi (the Negus) in Ethiopia. There we met Ja`far bin Abi Talib and stayed with him till we came (to Medina) by the time when the Prophet (ﷺ) had conquered Khaibar. The Prophet (ﷺ) said, "O you people of the ship! You will have (the reward of) two migrations."
Sahih al-Bukhari 3876