The Eleatics were a group of pre-Socratic philosophers and school of thought in the 5th century BC centered around the ancient Greek colony of Elea (Ἐλέα), located in present-day Campania in southern Italy, then known as Magna Graecia. The primary philosophers who are associated with the Eleatic doctrines are Parmenides, Zeno of Elea, and Melissus of Samos, although other Italian philosophers such as Xenophanes of Colophon and Empedocles have also sometimes been classified as members of this movement. The Eleatics have traditionally been seen as advocating a strict metaphysical view of monism in response to the materialist monism advocated by their predecessors, the Ionian school. Patricia Curd states that the chronology of pre-Socratic philosophers is one of the most contentious issues of pre-Socratic philosophy. Many of the historical details mentioned by Plato, Diogenes Laertius, or Apollodorus are generally considered by modern scholarship to be of little value, and there are generally few exact dates that can be verified, so most estimates of dates and relative chronology must rely on interpretations of the internal evidence within the surviving fragments. There is generally a consensus that Parmenides lived in the early 5th century BC, based on the date and setting of the fictionalized events in Plato's Parmenides where Parmenides and Zeno travel to Athens and have a debate with a young Socrates. This would place Parmenides well after other philosophers such as Xenophanes, Heraclitus, and Pythagoras. Although many philosophers throughout history have interpreted the doctrines of the Eleatics as responses to Xenophanes, Heraclitus, or Pythagoras, there is no broad agreement or direct evidence of any influence or direct response, although many theories have been put forth interpreting the eleatic in terms of these philosophers. For philosophers after Parmenides however, the relative chronology and potential directions of influence become even more difficult to determine.