Houghton House was built in 1621 by Mary, Countess of Pembroke and brother of the poet Sir Philip Sidney. In 1675, the house gave John Bunyan the idea for the 'House Beautiful' in his book "The Pilgrim's Progress". Bunyan's book is based on his own journey between Bedford and Luton. The steep slope leading into Ampthill was the model for the 'Hill of Difficulty'. Houghton House passed to the Duke of Bedford in 1738 and became a ruin after the roof was taken off in 1794.