Aquileja, or Aglar (Lat. Aquileia), an ancient town of Italy, situated at the head of the Adriatic about 22 miles west of Trieste. Colonised by Rome in 180 B.C., it rose to be one of the chief cities of the Empire with 130,000 inhabitants. Several councils of the Church were held here, and its bishops claimed the title of patriarch. Aquileja is now a mere village.