OfficinaOfficina (Latin, plural officinae) were workshops within Roman mints. During the early 3rd century Roman numerals I - IV were placed in the reverse fields of coins struck at the Rome mint to indicate the the officina within the mint that produced the coin. Most Roman coins struck after 274 carry officina marks, sometimes in the reverse field, but most often combined with the mintmark. At western mints the marks P, S, T, and Q indicated the prima (1st), secunda (2nd), tertia (3rd), and quarta (4th) officina. At eastern mints Greek numerals were used to indicate the officina from A (1st) to IE (15th).
Officina Numbers1stI, P (for prima), PRIMA, A (alpha), OFF P (officina prima)2ndII, S (for secunda), SECVNDA, B (beta), OFF S (officina secunda)3rdIII, T (for tertia), TERTIA, C, G (gamma)4thIIII, Q (for quarta), QVARTA, D, D (delta)5thV, E (epsilon)6thVI, V (stigma - archaic Greek letter resembling S)7thVII, Z (zeta)8thH (eta)9thN, Q (theta), DE (delta epsilon)10thX, I (iota)11thXI, IA (iota alpha), AI (alpha iota)12thXII, IB (iota beta), BI (beta iota)13thIG (iota gamma), GI (gamma iota)14thID (iota delta), DI (delta iota)15thIE (iota epsilon), EI (epsilon iota)