See the amusing letters of Pietro della Valle, the Roman traveler, (Viaggi, tom. ii. 207, 209, 213, 215, 266, 286, 300, tom. iii. p. 54, 127.) In the years 1618, 1619, and 1620, he conversed with Shah Abbas, and strongly encouraged a design which might have united Persia and Europe against their common enemy the Turk.