Christianity spread fast in Nigeria because it

The history of Christianity in Nigeria can be traced back to the 15th century, when the Portuguese were the first Europeans to arrive the shores of the region via the Atlantic.  The Portuguese brought Christianity with them but were unable to successfully plant Christianity because of their involvement in slave trade. It can be argued that the actual intent behind their voyage was more in the interest of slave business, than it was for missionary goals and objectives. Most of the Portuguese slave traders took Nigerian slaves to be resold in the Americas and parts of Europe. Hence, they were not committed to missionary work.

After the abolition of the slave trade in the British Empire in 1833, things took an interesting turn. Slaves captured by European masters were freed and sent to Freetown in Sierra Leone. These slaves had lived with their masters in Europe and America, and many had accepted Christianity at the time they were freed. In 1841, freed slaves arrived in Sierra Leone and gradual changes began in British policies. Slavery was frowned upon, and the British government took it upon itself to enforce new laws and policies, in a bid to stop trading and owning slaves.

Towards the end of the 19th century, some of the freed slaves began to retrace their ways back home. Freed slaves from Nigeria sailed from Sierra Leone to Lagos and Badagry on vessels acquired from slave courts in Freetown. Some of the freed slaves settled in Abeokuta (capital of Ogun State) and other cities in western Nigeria. They also had opportunities to acquire education offered by the Church Missionary Society (CMS). They practiced Christianity and preached the gospel to their family and kinsmen.  Over time, a good number of former slaves converted to Christianity. One of those slaves worthy of mention was Samuel Ajayi Crowther. He was captured at age 12 by Fulani slave raiders and sold to Portuguese slave traders. He later regained his freedom and went on to become the first African to be ordained bishop by the Christian Missionary Society (CMS) in addition to his consecration as bishop of the Niger territory. Samuel was one of the pioneers of local Christian missionary work in Nigeria and contributed to the translation of the Bible into Yoruba language.