Well, the Hijri date 18 Jumada Al Oula 1266 corresponds to the Gregorian date Sunday, 31 March 1850. This date lies in the fifth month of the Hijri year 1266 AH, which is Jumada Al-Awwal of 1266 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1266/05/18 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 31 March 1850 to its equivalent Arabic date.
The following is the conversion of the Arabic date 18 Jumada Al Oula 1266 AH to its equivalent Gregorian date.
كَذَٰلِكَ أَرْسَلْنَٰكَ فِىٓ أُمَّةٍۢ قَدْ خَلَتْ مِن قَبْلِهَآ أُمَمٌۭ لِّتَتْلُوَا۟ عَلَيْهِمُ ٱلَّذِىٓ أَوْحَيْنَآ إِلَيْكَ وَهُمْ يَكْفُرُونَ بِٱلرَّحْمَٰنِ ۚ قُلْ هُوَ رَبِّى لَآ إِلَٰهَ إِلَّا هُوَ عَلَيْهِ تَوَكَّلْتُ وَإِلَيْهِ مَتَابِ
Thus We send thee (O Muhammad) unto a nation, before whom other nations have passed away, that thou mayst recite unto them that which We have inspired in thee, while they are disbelievers in the Beneficent. Say: He is my Lord; there is no Allah save Him. In Him do I put my trust and unto Him is my recourse.
Surah Ar-Ra'd(13:30)