He was born on 25 December, Christmas Day, 1822, son of Thomas Nelson then a bookseller, and his wife, Margaret Black.
In 1844 the firm moved to larger premises in Hope Park in Edinburgh's South Side.
[3] In 1869 Thomas commissioned John Lessels to build St Leonards, a very large baronial mansion close to his premises, built in the grounds of Abden House.
The building now forms part of Edinburgh University's Pollock Halls of Residence.
Their son Thomas Arthur Nelson was a Captain in the Lothians and Border Horse in the First World War and was killed at Arras in April 1917.