Sir Lionel Tollemache (bpt 25 April 1624 - bur 25 March 1669) 3rd Baronet of Helmingham was the head of a powerful East Anglian family whose seat was Helmingham Hall in Suffolk, England. He was the son of Sir Lionel Tollemache, 2nd Baronet and Elizabeth Stanhope, an heiress of Lord Harrington.
Around 1648, Tollemache married Elizabeth Murray, the daughter of William Murray, 1st Earl of Dysart and 'whipping boy' to King Charles I. He and his wife, who were both fervent royalists, moved to her house at Ham in Surrey, which in due course became a centre for the activities of the Sealed Knot. Together they were in contact with Charles Stuart, later Charles II, then in exile on the continent. Rather surprisingly however, Elizabeth was also said to be on very good terms with the Lord Protector, Oliver Cromwell, leading to claims that he was the real father of some of her children, since discounted.
Tollemache appears to have been plagued with ill-health throughout much of his life. Augustus Hare, in The Story of My Life (1900) suggested that this was as a result of his being slowly poisoned by his wife, who had used up his fortune turning Ham House into a grand palace and now needed new sources of income with which to pay off her creditors. There is no evidence to back up such a claim however and it must be seen that Elizabeth's reputation has suffered from its subsequent association with that of her second husband, John Maitland, 1st Duke of Lauderdale, whom it was said she charmed even as her husband 's health deteriorated. Tollemache travelled to France in search of cures for his debilitating sickness, but died in Paris. In 1670 Elizabeth obtained confirmation from King Charles that she could pass on the title of Earl of Dysart to any one of her children.