The monarch made the announcement public on Friday when he received the leadership of Immaculate Conception College (ICC) old students.
The mother is the traditional ruler’s fifth and youngest wife.
The king also revealed the sexes of the new members of the royal family – three boys and one girl.
The Ewuare II thanked God and his ancestors for the blessing.
Ohen-Osa Igbinoghodua Edebiri, the Priest of Holy Aruosa Church offered prayers for the babies.
In May 2020, the 40th Oba of Benin welcomed his first child after ascending the throne. The Prince was delivered by Princess (Oloi) Iyayota.
The birth of the quadruplets is being celebrated at the palace and the people of Benin kingdom home and abroad.