Originally a theoretical principle of classification of astronomical and augural ( A ugures ) practice (Cic. Div. 1,17; 1,30; 2,3; 2,9; Ov. Ib. 38; Cic. Nat. D. 2,19; 2,50), elements of the division of Rome into four parts by Servius Tullius (Varro, Ling. 5,45; 49; 51; 53; Liv. 1,43,13; Plin. HN 18,13; Paul. Fest. 506,5), which was transferred to the tribus : I. Suburana, II. Esquilina, III. Collina, IV. Palatina (Rome III with map 3).
Augustus partitioned the city, which had grown prodigiously in the meantime, into 14 regiones (10-4 BC; Suet. Aug. 30,1; [2]), still …