Not much is known about the philosopher’s early life, not even his exact dates of birth and death. He is believed to be born in the city of Miletus, an ancient Greek Ionian city on the western coast of Asia Minor in today’s Turkey. The time of his life was calculated on the basis of events related to him in the later sources, most notably in the work “Lives and Opinions of Eminent Philosophers” by Diogenes Laertius (c. 3rd century BCE) who wrote biographies of ancient Greek philosophers and one of the most important sources for ancient Greek philosophy. Laertius tells us that according to the chronicle by Apollodorus of Athens, Thales of Miletus died in the 58th Olympiad aged 78. Since the 58th Olympiad was the period between 548 and 545 BCE, Thales of Miletus was born sometime between 626 and 623 BCE.
According to Laertius who quotes Herodotus, Douris and Democritus, Thales’ parents were Examyes and Cleobuline who are thought to had been of Phoenician origin and well financially situated. As much as his later life is concerned, there are a lot of conflicting information. According to some sources, Thales was married and had a son named Cybisthus but according to other, he never married and adopted his nephew Cybisthus.