Read this and answer the question

The proximity of the Palace of Westminster did not extend to providing monks or abbots with high royal connections; in social origin the Benedictines of Westminster were as modest as most of the order. The abbot remained Lord of the Manor of Westminster as a town of two to three thousand persons grew around it: as a consumer and employer on a grand scale the monastery helped fuel the town economy, and relations with the town remained unusually cordial, but no enfranchising charter was issued during the Middle Ages. The abbey built shops and dwellings on the west side, encroaching upon the sanctuary.[citation needed]

What encroached upon the sanctuary?
shops and dwellings