Marianne was born in 1813 in Beckenham and her baptism took place there on January 2nd, 1814.1 Marianne's father was Shock Letts and her mother was Sarah Denny. Her paternal grandparents were John Letts and Amy Weller. She had two brothers and three sisters, named Henry, Stephen, Amy, Frances and Sarah. She was the oldest of the six children.