P / prŏbātōrĭa
noun

prŏbātōrĭa

gen. prŏbātōriae · gender feminine · decl. 1st
(sc. epistula) [id.]
a letter of recommendation; a certificate of qualification
a letter of recommendation (from the emperor), a certificate of qualification (postclass.): sacra probatoria, Cod. Just. 12, 58, 2: emissa sacri scrinii probatoria, ib. 12, 60, 6; 12, 36, 7.