The parish church of Bonnington is dedicated to St. Rumwold an Anglo Saxon saint who was reputedly born in AD662, son of King Alchfrid of the royal house of Northumbria and his queen, St. Cyneburga. Legend has it that he lived only three days and was born with the gift of speech professing his faith on his first day of life. On his second day he made many discourses, according to Fuller, "on all commonplaces of popery" and on his third day of life he addressed a sermon to his parents then died.

The church is mainly Norman with some signs of Saxon long-and-short work and is reputed to be the oldest of the Romney Marsh churches.