Philippopolis is Plovdiv, Bulgaria today. A Neolithic settlement dating around 4000 B.C. establishes Plovdiv as among the world's oldest cities. It was a walled Thracian city called Eumolpias when it was conquered by Philip II of Macedon, the father of Alexander the Great. He renamed it Philippopolis. When it regained independence, the new Thracian name was Pulpudeva. In Latin it was sometimes called Trimontium (City of Three Hills). An important crossroads in the Roman Empire, it became the capital of Roman Thracia.