Muslims deny that Jesus was crucified. In Islam, Jesus is a prophet of Allah and (as the Muslim logic goes) it would be an abomination for one of Allah’s chosen prophets to die such a humilating death.
They believe he was swapped out at the last minute and it is believed that Judas was the one crucified.
Jesus probably died around the year 30 and the Koran was not finalized until 632, with the death of Muhammed. The actual Koran was not compiled until the 640’s-650’s after much research was done to see what were Muahmmed’s sayings and revelations and which ones were not.
Muhammed lived from 570 - 632, so over 500 years after Jesus. Islam appeared along with Muhammed during Muhammed’s lifetime and began to take off ever since.
Ironically enough, the Koran in Sura 19 quotes Jesus speaking as an infant (this is one of his miracles according to Islam): “Peace be on me the day I was born, the day I will die, and the day I am risen back alive.” This is a contradictory statement to Islamic theologians. They deny that Allah’s prohets could be killed (nevermind the other prophets before Jesus who were killed before him) but yet apparently the infant Jesus spoke about his own death.
*In the Koran, sura is the same as a chapter.
Once you begin reading the Koran along with Catholic supplementals, you will realize that Catholicism is the only one true faith. But there is no denying the impact Islam is and continues to have on the world.