Geocentric model knew about Tusi's work or that of the Maragha school. Not all Greeks agreed with the geocentric model. The Pythagorean system has already been mentioned; some Pythagoreans believed the Earth to be one of several planets going around a central fire. Hicetas and Ecphantus, two Pythagoreans of the 5th century BC, and Heraclides Ponticus in the 4th century BC, believed that the Earth rotated on its axis but remained at the center of the universe. Such a system still qualifies as geocentric. It was revived in the Middle Ages by Jean Buridan. Heraclides Ponticus was once thought to have proposed
Amherst Central Business District Amherst Central Business District The Amherst Central Business District is a historic district encompassing the heart of downtown Amherst, Massachusetts. Centered on the northern section of the long town common, the area has been the civic and commercial heart of the town since the 18th century. The district was listed on the National Register of Historic Places in 1991, and slightly enlarged in 2011. Amherst was originally part of Hadley, settled in 1661, and was itself known to have colonial settlements by 1728. It was incorporated in 1768. Its earliest focal point of settlement was in what is now its