When Vasco da Gama sailed into Malindi in 1498, he carried more than a flag and cannons. He carried Christianity, and the Portuguese were determined to spread it along with their trade empire. They built churches alongside their fortifications.
They baptised some coastal leaders. They attempted, with limited success, to convert communities that had been Muslim for centuries. Christianity did not take root on the Kenyan coast under the Portuguese.
That would come later, in the interior, carried by British missionaries who arrived three centuries later with Bibles and the conviction that they were doing God's work.