Sentence:  With some of it on the south and more of it on the north of the great main thoroughfare that connects Aldgate and the East India Docks, St. Bede's at this <WSD>period</WSD> of its history was perhaps the poorest and most miserable parish in the East End of London. 
Meaning of the word marked with <WSD> tags:  A period of time in history seen as a single coherent entity; an epoch, era. (from 16th c.)