Well, the Hijri date 17 Shawwal 1255 corresponds to the Gregorian date Monday, 23 December 1839. This date lies in the tenth month of the Hijri year 1255 AH, which is Shawwal of 1255 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1255/10/17 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 23 December 1839 to its equivalent Arabic date.
The following is the conversion of the Arabic date 17 Shawwal 1255 AH to its equivalent Gregorian date.
ثُمَّ يَوْمَ ٱلْقِيَٰمَةِ يُخْزِيهِمْ وَيَقُولُ أَيْنَ شُرَكَآءِىَ ٱلَّذِينَ كُنتُمْ تُشَٰٓقُّونَ فِيهِمْ ۚ قَالَ ٱلَّذِينَ أُوتُوا۟ ٱلْعِلْمَ إِنَّ ٱلْخِزْىَ ٱلْيَوْمَ وَٱلسُّوٓءَ عَلَى ٱلْكَٰفِرِينَ
Then on the Day of Resurrection He will disgrace them and will say: Where are My partners, for whose sake ye opposed (My guidance)? Those who have been given knowledge will say: Disgrace this day and evil are upon the disbelievers,
Surah An-Nahl(16:27)