Hazrat Umar Invented the Islamic Calendar
The dating of the Islamic calendar was introduced by the second caliph, `Umar ibn Al-Khattab, in 638 CE (16 AH) in an attempt to circumvent all the various conflicting dating systems used during his time.
After consulting his companions, he set the Hijrah—the immigration of the Prophet (peace and blessings be upon him) from Makkah to Madinah—as the most appropriate reference to the new Islamic era.
Put your glasses and see the date,. it is 638CE few years after Prophet was around. There was not a islamic calendar at the time of our prophet (peace be upon him)