Wikipedia says: "Thought to be the namesake of John Montagu, 4th Earl of Sandwich, following the claim that he was the eponymous inventor of the sandwich." and... "The ancient Jewish sage Hillel the Elder is said to have wrapped meat from the Paschal lamb and bitter herbs between two pieces of old-fashioned soft matzah, flat, unleavened bread, during Passover in the manner of a modern sandwich wrap made with flatbread. Flat breads of only slightly varying kinds have long been used to scoop or wrap small amounts of food en route from platter to mouth throughout Western Asia and northern Africa. From Morocco to Ethiopia to India, bread is baked in flat rounds, contrasting with the European loaf tradition."
the Earl of Sandwich part is true. he was playing cards with his friends and his maid bought a roast dinner to him and he didn't want to stop playing so he told her to put the roast meat inbetween 2 slice of bread with the gravy spread on the sides.