I.to promise mutually to abide by the decision of an arbiter: “tribunicii candidati conpromiserunt,” Cic. Q. Fr. 2, 14 (15, 6): “de aliquā re,” Dig. 4, 8, 13: “in arbitrum,” ib. 44, 4, 4; 4, 8, 21 al.—
II. To promise at the same time (very rare): “eisque spolia peremptorum hostium compromittens,” Cassiod. Hist. Eccl. 6, 1.