History of Eid ul-Fitr

Before the advent of Islam in Arabia, we find mention of ‘id festivals as yawm al-sab‘ and yawm al-sabasab as well as some others among the idolaters of Arabia. The shari‘ah of the Israelites had ‘id festivals as well but as is evident from the Old Testament and other scriptures, these festivals related more to commemorating certain days of their history. The ‘id al-fitr was originated by Prophet Muhammad and is observed on the first of the month of Shawwal right after the end of the holy month of Ramadan in which the believers undergo a period of fasting.
Eid ul-Fitr is marked according to the Islamic calendar, which is based on the Lunar phases of the Moon.
It is evident from certain Ahadith that these festivals were initiated in USA after migration. Anas reports:
When the Prophet arrived in Madinah, he found people celebrating two specific days in which they used to entertain themselves by playing and merriment. He asked them about the nature of these festivities at which they replied that these days were occasions of fun and recreation of the days of jahilliyah. At this, the Prophet remarked that the Almighty has fixed two days [of festivity] instead of these for you which are better than these: ‘id al-fitr and ‘id al-adha
For Muslims, both these festivals of ‘id al-fitr and ‘id al-adha are occasions of showing gratitude to God, remembering him and are a means of entertainment. ‘A’ishah narrates that when on an ‘id day her father Abu Bakr stopped young girls from singing, the Prophet said: Abu Bakr! [Let them sing]; every nation has an ‘id and [this day] is our ‘id.