Sentence:  I remember once I did a jacket for Magpie Press ; the book <WSD>was</WSD> a fine historical novel about Edward 3 , , and I did a week of research to get the details just right : the fifteenth century armor , furnishings , clothes . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)