Short answers, pulled from the story.
Thales of Miletus, born around 625 BC in Ionia, is recognized as the first philosopher in Western philosophy. He identified water as the arche, or first principle, of the world, and he is distinguished as the first philosopher because he used observation and reason to reach that conclusion.
The word philosophy comes from the Ancient Greek philosophia, literally the love of wisdom. It joins philein, meaning to love, with sophia, meaning wisdom.
Socrates was tried by the Athenian democracy on charges of impiety and corrupting the youth, found guilty, and sentenced to death. His execution consisted of drinking poison hemlock, and he died in 399 BC after refusing his friends' offer to help him escape from prison.
Aristotle proposed the four causes, material, efficient, formal, and final, to explain change. All four were grounded on what he termed the unmoved mover, and he offered them in place of Plato's metaphysics, which he faulted for failing to explain change.
Analytic philosophy focuses on epistemology, ethics, law, and politics, stressing detailed argumentation and clarity of meaning, and is more common in the English-speaking world. Continental philosophy leans toward general frameworks of metaphysics and gathers movements such as phenomenology, existentialism, structuralism, and post-structuralism, and is more common in mainland Europe.
Pyrrho of Elis traveled to India with Alexander the Great's army and was influenced by Buddhist teachings, especially the three marks of existence. Returning to Greece, he founded Pyrrhonism, whose goal of ataraxia has been compared to nirvana and the Buddhist Madhyamika school. Some interpreters also link David Hume's view of the self to Buddhist thought.