Andreas is a masculine given name derived from the Greek name Ανδρέας (Andréas). The name originates from the ancient Greek word "ἀνήρ" (anēr) meaning "man". It is composed of the prefix "andr-" meaning "man" and the root "-as" found in many Greek names.

The name Andreas has been in use since ancient times in Greece and the wider Hellenic world. It was a popular name among early Christians, possibly due to the apostle Andrew who was one of the Twelve Apostles of Jesus Christ. The name is mentioned in the New Testament as one of the earliest followers of Jesus.

One of the earliest known bearers of the name was Andreas of Caesarea, a 6th-century Byzantine historian and scholar. Another notable early figure was Andreas Palaiologos, a 13th-century Byzantine prince and grandson of Emperor Michael VIII Palaiologos.

In the Middle Ages, the name was widespread across Europe, particularly in regions influenced by Greek or Byzantine culture. Andreas Capellanus, a 12th-century French philosopher and author, wrote the influential treatise "De Amore" on the art of courtly love.

During the Renaissance, Andreas Vesalius, a 16th-century Flemish anatomist and physician, is considered the founder of modern human anatomy. His work "De Humani Corporis Fabrica" was a groundbreaking anatomical text.

Other notable individuals named Andreas include Andreas Gryphius (1616-1664), a German poet and playwright; Andreas Schlüter (1659-1714), a German baroque sculptor and architect; and Andreas Hofer (1767-1810), a Tyrolean innkeeper and patriotic leader during the Napoleonic Wars.

In more recent times, Andreas Baader (1943-1977) was a founding member of the West German militant group Rote Armee Fraktion (Red Army Faction), while Andreas Papandreou (1919-1996) was a Greek economist and politician who served as Prime Minister of Greece.