Via Militaris or Via Diagonalis was an ancient Roman road, starting from Singidunum (today the Serbian capital Belgrade), passing by Danube coast to Viminacium (modern Požarevac), through Naissus (modern Niš), Serdica (modern Sofia), Philippopolis (modern Plovdiv), Adrianopolis (modern Edirne in Turkish Thrace), and reaching Constantinople (modern Istanbul). This road was connected with Via Egnatia by other roads: the road along the Axios (or Vardar) River, the road from Serdica to Thessalonica along the Strymon (or Struma) River, and the road from Philippopolis to Philippi.