Sentence:  That our work, therefore, might be in no danger of being likened to the labours of these historians, we have taken every <WSD>occasion</WSD> of interspersing through the whole sundry similes, descriptions, and other kind of poetical embellishments. 
Meaning of the word marked with <WSD> tags:  A favorable opportunity; a convenient or timely chance. (from 14th c.)