It is mentioned in the Hadith that a delegation from Yemen came to the prophet (PBUH), and asked him:
"O Allah's Apostle! We have come to ask you about this matter (i.e. how creation began)".

The prophet understood that this question needs an answer in order to prevent any misinterpretations resulting from vain desire or Satanic thoughts, so he said:

"First of all, there was Allah, and there was nothing before Him,

The first thing that Allah created was the pen
and He said to it 'Write'.
The pen asked, "O my God... What shall I write?'
Allah said, 'Write (the) fate (of everything).'

So the pen wrote everything that shall be from that moment until judgment day.
and He wrote everything in "Al-Thikr" (the tablet)
and then He created the Heavens and the Earth."

Volume 4, Book 54, Number 416:

Narrated Abu Huraira:
Allah's Apostle said, "When Allah completed the creation, He wrote in His Book which is with Him on His Throne,

"My Mercy overpowers My Anger."

Answered by Ashish Yadav , an ibibo Wizard, at 6:46 PM on November 08, 2008