The question "what happened on 8 Rabi ul Awal" is a bit vague and could refer to different events that happened on that day throughout history. However, based on the search results, here are some significant events that happened on 8 Rabi ul Awal:

• On the eighth of Rabi’ al-Awwal AH 260, Imam al-Hasan al-’Askari departed life; and his son, the Patron of the Age, was appointed as the twelfth Imam.
• Some sources have proposed that the first meeting between the Prophet and the angel Gabriel occurred in Rabiul Awwal as he was appointed as a prophet at the beginning of his forty.
• There were some other less known or disputed events reported in historical references that took place in Rabiul Awwal.

It is important to note that Rabi ul Awal is an important month in the Islamic calendar as it marks the birth of the Prophet Muhammad (PBUH) .