Capitulation is a document containing the terms of surrender. In this case, it means that someone has surrendered to the nation that the sentence is refering to. E.g.: "The Blues were capitulated by the Greens" would mean that the blues have surrendered to the greens. A capitulation document can contain any terms at all. When capitulated, a nation gets 2 turns, and the master gets 3.


The Vassal is the name for the person that has surrendered, in this case it would be the blues. The Vassal has to then become under the Master's rule.


The Master is the name for the person that has capitulated, in this case if would be the greens. The Master can impose the Vassals to commit any action they like. The Master, however, uses 0.5 turns in doing this and it costs the Vassal 1 turn.