Alexander III of Macedon, commonly known as Alexander the Great (July 20/21, 356 BC – June 10/11, 323 BC), was the 14th basileus (king) of the Argead dynasty of the Kingdom of Macedon. Ancient Macedonia. During his military career, Alexander conquered almost the entire world known to Europeans at the time before his death and is therefore often considered one of the most successful generals, as well as a one of the greatest military strategists in history.