The Greek Archelaus (meaning 'ruling the people') is a proper name appearing once in the NT (Matthew 2:22). He was the son of Herod the Great who ruled Judea, Samaria, and Idumea (4 BC – 6 AD) after his father's death, though with the lesser title of ethnarch rather than king.
Matthew 2:22 explains why Joseph, warned in a dream, avoided Judea and settled instead in Galilee: 'When he heard that Archelaus was reigning in Judea in place of his father Herod, he was afraid to go there. Having been warned in a dream, he withdrew to the district of Galilee.' Archelaus was notorious for cruelty — he massacred 3,000 pilgrims at Passover, was condemned even by his own people, and was eventually exiled by Augustus. His reign becomes the instrument of fulfilled prophecy: because of Archelaus' cruelty, Jesus grew up in Nazareth — 'so was fulfilled what was said through the prophets, that he would be called a Nazarene' (Matthew 2:23). Even the wickedness of human rulers serves God's sovereign purposes for His Son.