Passage: During his early youth, Dodgson was educated at home. His "reading lists" preserved in the family archives testify to a precocious intellect: at the age of seven, he was reading books such as The Pilgrim's Progress. He also suffered from a stammer – a condition shared by most of his siblings – that often influenced his social life throughout his years. At the age of twelve he was sent to Richmond Grammar School (now part of Richmond School) at nearby Richmond.

Question: at what age was he enrolled?
age of twelve