Complex sentence: C.H. Mackintosh's mother was Leonora Sophia, daughter of Col. Dickinson, of Jamaica, West Indies, who claimed to be close kin to Sir Stamford Raffles, founder of Singapore, one of whose sisters was called Leonora.
Split into simpler sentences: C.H. Mackintosh's mother was Leonora Sophia, daughter of Col. Dickinson, of Jamaica, West Indies. Through the maternal line, Mackintosh claimed to be close kin to Sir Stamford Raffles, founder of Singapore, one of whose sisters was called Leonora.