37 Fides is a large main-belt asteroid. It was discovered by German astronomer Karl Theodor Robert Luther on October 5, 1855, and named after Fides, the Roman goddess of loyalty. Fides was the last of the main-belt asteroids to be assigned an iconic symbol, a Latin cross U+271D ✝. 37 Fides is also a S-type asteroid in the Tholen classification system.