Matthew DeFoe is the twin brother of John DeFoe and son of Sir Roderick DeFoe. His mother, Belinda, died after giving birth to John DeFoe, whom Sir Roderick bitterly resented as a consequence. Matthew therefore grew up with no knowledge of his twin, who was kept locked in a cellar, tied up with manacles. Trilby remarks, after having read Matthew's diary, that he may not have been "the sharpest knife in the drawer".