# Saccheri, Giovanni Girolamo (1667–1733)

Giovanni Saccheri was a Jesuit priest, philosopher, and mathematician who did early
work on non-Euclidean geometry,
although he didn't see it as such. His *Euclides ab Omni Naevo Vindicatus* (1733) was actually an attempt to prove Euclid's parallel
postulate but ended up laying the groundwork for both hyperbolic
geometry and elliptical geometry.