Festivities (A random thought)

(I didn't use the word "festival" because it brings in different connotations with it)
I always wonder about the origins of things ...I try and imagine how they beginnings ... how they progressed through time ...finally to their current states.
For example, now a days,we celebrate Eidul Azha with a number of established events and rituals.On my side of the world (Where I belong to),on Eid day,after Fajar Prayers,men go to graveyards to pray for their beloved deceased.After that, they offer Eid prayers then some of us go to meet relatives first but most of us start getting ready for the ritual of the animal sacrifice.After the completion of that comes the process of distribution and hence most of the days passes.
This Eid has a well known origin....but have you ever wondered that in what ways it used to be different from its current form?Surely the sacrifice of the animal has been consistent form the start ...as its the main event ... But what about the events leading to it ...?What about the events after it ... ?
P.S:This post is a random thought that I wanted to share with you guys.