Lettice (or Letitia) Morison (or Moryson) was born c. 1612 to mother Mary and father Sir Richard, who was Lieutenant-General of the Ordnance.

[1] She spent her childhood at Tooley Park in Leicestershire, then in 1630 married a friend of her brother, Sir Lucius Cary.

[1] Her husband's father the 1st Viscount Falkland was against the marriage because she was not wealthy and so they moved to the Dutch Republic, in the Hague, where he sought military employment.

[1][5] Together the couple hosted the Great Tew Circle in the 1630s, a discussion group based on the teachings of Jacobus Arminius which featured philosopher William Chillingworth and historian Edward Hyde who later became 1st Earl of Clarendon and Lord Chancellor.

[1] Hyde described Cary as "a lady of most extraordinary wit and judgement, and of the most signal virtue and exemplary life that the age produced".