The practice of circumcising males on the 8th day of birth was a practice brought to Igboland, as well as other places in Africa, by European colonial missionaries. As widely known, circumcision on the 8th day is a requirement for all Christian males. It is a symbol that the child is a spiritual descendant of Abraham. The Igbo, like many other Africans who embraced Christianity, embraced to an extent this practice of circumcision on the 8th-day of birth. However, as rightly said earlier, this was never Igbo tradition.We had already been practicing circumcision, and we had our own time frames of when to conduct circumcision:

http://www.dedechibublog.com/2017/11/traditional-igbo-circumcision-and-8th_24.html