Lion Heart by Justin Cartwright

Richard Cathar recalls his recently deceased father, Alfric, as a delusional hippie, one who fancied himself an intellectual and historian. One of many far-fetched claims was that he had discovered-and then lost-documentation of a meeting between his hero, Richard the Lionheart, the scrappy Robin Hood, and the great sultan Saladin. Further, he had seen proof that Richard the Lionheart reclaimed from Saladin, at that meeting, the True Cross.

Hoping to sort out the fact and fiction of his father's life, Richard (named for the great king) travels to Jerusalem to follow the trail of the holy relic, a journey that takes him throughout the Middle East and Europe, kicking up romance, mystery, and self-reckoning.
Justin Cartwright's latest novel is an utter original -- exciting, funny, and profound.