 Corbet continued to progress and to prosper throughout Mary's reign, although his Protestant sympathies must have been apparent from the outset.Corbet was elected Member (MP) for Shropshire in the Parliament of England summoned on 3 September 1555 – the fourth and penultimate of Mary's reign.He was returned, first in order of precedence, with Sir Henry Stafford, a nonentity who had failed twice to secure election in Staffordshire, where his family had great influence.