Spiru Haret, Romanian mathematician, astronomer, and politician, 55th Romanian Minister of Internal Affairs (d. 1912)
Spiru C. Haret (Romanian pronunciation: [ˈspiru haˈret]; 15 February 1851 – 17 December 1912) was an Romanian mathematician, astronomer, and politician. He made a fundamental contribution to the n-body problem in celestial mechanics by proving that using a third degree approximation for the disturbing forces implies instability of the major axes of the orbits, and by introducing the concept of secular perturbations in relation to this.
As a politician, during his three terms as Minister of Education, Haret ran deep reforms, building the modern Romanian education system. He was made a full member of the Romanian Academy in 1892.
He also founded the Bucharest Observatory, appointing Nicolae Coculescu as its first director. The crater Haret on the Moon is named after him.