In 1672 Bunyan was set free, and allowed to begin again his work as a Baptist minister, and he soon became one of the most popular preachers in all England. He died quite suddenly in 1688, when he was sixty years old, and is buried in an old graveyard now near the center of London, called Bunhill Fields Burial-ground. In the same ground is buried another great writer, Daniel DeFoe, whose story of "Robinson Crusoe" ranks next to the Pilgrim's Progress in the number of its readers; also Isaac Watts, the author of many hymns sung in all the churches, and Mrs. Susanna Wesley, the mother of the great John Wesley. Four people who have left a deep mark upon the world, all lie near together in this small cemetery in London.