Sentence:  By his <WSD>marriage</WSD> to his two wives, Tapuwae quietly strengthened all of the "pas" of the Wairoa district, as many of them came under his control through these unions. 
Meaning of the word marked with <WSD> tags:  A union of two or more people that creates a family tie and carries legal, social, and/or religious rights and responsibilities. (from 14th c.<ref name="etymonline"></ref>)