When were Eid al-Adha and Eid al-Fitr mandated?

Eid al-Fitr and Eid al-Adha were legislated in Medina in the second year of the Prophet's migration (Hijra). Scholars have agreed that the first Eid prayer performed by the Prophet, peace and blessings be upon him, was Eid al-Fitr in the second year of the Hijra, which was also the year Ramadan was made obligatory.

Anas's hadith indicates that the Prophet, peace and blessings be upon him, replaced the two days of Jahiliyyah (pre-Islamic era) play with the days of Eid al-Fitr and Eid al-Adha. Some biographers also mentioned that the first Eid prayer performed by the Prophet, peace and blessings be upon him, was Eid al-Adha in the second year of the Hijra, during which he sacrificed two sheep at the prayer ground (musalla).

Ibn Kathir is of the view that it is not unlikely the Prophet, peace and blessings be upon him, was preoccupied with the Ghazwat Bani Salim (expedition) and thus missed the Eid al-Fitr prayer.