Laylatul Qadr (the Night of Power) Laylat Al-Qadr is the anniversary of the night Muslims believe the first verses of the Quran were revealed to Muhammad by the angel Gabriel (Jibril in Arabic). It is also the anniversary of the night in which the Quran is believed by Muslims to have been revealed in its entirety. The Laylat Al-Qadr is also be known as the night of excellence.
Doua on that day Aishah (radhiya Allahu Ta'ala anha), that she said: "O Messenger of Allah! What if I knew which night Lailatul-Qadr was, then what should I say in it?" He said 'Say اَللَّهُمَّ اِنَّكَ عَفُوٌّ ، تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي Allahumma innaka 'affuwwun tuhibbul 'afwa fa'fu 'anni' " O Allah You are The One Who pardons greatly, and loves to pardon, so pardon me.
Laylat al-Qadr is to be found in the last 10 nights of Ramadan. There is no history in the Quran as to when the specific date is. In Sumatra and Morocco it is celebrated on 27 Ramadan,   but other cultures celebrate it on the 19th, 21st, 23rd, 25th ,27 and 29th.