The Greek astronomer Aristarchus of Samos (310–230 BCE) was the first to propose a heliocentric model of the universe, with the Sun at the center and all the planets orbiting it.[50] Aristarchus's model was widely rejected because it was believed to violate the laws of physics.[50] The inventor and mathematician Archimedes of Syracuse made major contributions to the beginnings of calculus[51] and has sometimes been credited as its inventor,[51] although his proto-calculus lacked several defining features.[51] Pliny the Elder was a Roman writer and polymath, who wrote the seminal encyclopedia Natural History,[52][53][54] dealing with history, geography, medicine, astronomy, earth science, botany, and zoology.[52] Other scientists or proto-scientists in Antiquity were Theophrastus, Euclid, Herophilos, Hipparchus, Ptolemy, and Galen.