Pythagoras the Samian was an Ionian Greek philosopher, mathematician, and founder of the religious movement called Pythagoreanism. Most of the information about Pythagoras was written down centuries after he lived, so very little reliable information is known about him. He was born on the island of Samos, and might have travelled widely in his youth, visiting Egypt and other places seeking knowledge. Pythagoras made influential contributions to philosophy and religion in the late 6th century BCE. He is often revered as a great mathematician, mystic, and scientist and is best known for the Pythagorean theorem which bears his name.