A History of Greek Philosophy / THE SCHOOL OF MILETUS / ANAXIMANDER
This philosopher is said to have been younger by one generation than Thales, but to have been intimate with him. He, like Thales, was a native of Miletus, and while we do not hear of him as a person, like Thales, of political eminence and activity, he was certainly the equal, if not the superior, of Thales in mathematical and scientific ability. He is said to have either invented or at least made known to Greece the construction of the sun-dial. He was associated with Hecataeus in the construction of the earliest geographical charts or maps; he devoted himself with some success to the science of astronomy. His familiarity with the abstractions of mathematics perhaps accounts for the more abstract form, in which he expressed his idea of the principle of all things.
Cf. Anaximander Resources / Guthrie, The Early Presocratics and the Pythagoreans - A Synopsis of Greek Philosophy
Reference address : https://www.ellopos.net/elpenor/greek-texts/ancient-greece/history-of-philosophy/anaximander.asp