an altar erected in 28 A.D. by order of the senate, dedicated to the amicitia of Tiberius, probably as illustrated in the case of Sejanus (Tac. Ann. iv. 74
: ita quamquam diversis super rebus consulerentur, aram clementiae, aram amicitiae effigiesque circum Caesaris ac Seiani censuere
; cf. Wissowa, Rel. 337). Its site is entirely unknown.