The Collaborative International Dictionary of English v.0.48:
Embassage \Em"bas*sage\ (?; 48), n. 1. An embassy. "He sent a solemn embassage." --Bacon. [1913 Webster] Except your embassages have better success. --Motley. [1913 Webster] 2. Message; errand. --Shak. [1913 Webster]