What is it?
There is an ancient Hindu king tradition – the ashwamegha yagna
A sovereign king would take a stallion and release it in the forrest. He would be followed by a group of royal members of the king and the horse roams freely. When it goes into the territory of the nearby kingdom the neighbor has to accept the sovereign king as a master or capture the horse and fight the king. The horse was allowed to roam for 6 or 12 months.
At the end of the year the horse guys back to the king. A big ceremony follows. The head of the horse is severed. The queen spends a night with the dead horse. The horses tendons are then cut and the ceremony is concluded
Bhavin