Published in 1869, this account of a trip east to the Old World was a great popular success. Within its first year it sold over 70,000 copies, and it remained the best-selling of MT's books throughout his lifetime. The book began as a series of travel letters written mainly for the Alta California, a San Francisco paper that sponsored MT's participation in the Quaker City trip to Europe and the Holy Land in 1867. Revising the letters into a book was suggested by Elisha Bliss, who published Innocents as a subscription book on July 20th, 1869.