Ralph Shaa

Ralph Shaa (died 1484), (sometimes erroneously called John Shaa), was a 15th-century English theologian, the half-brother of the Lord Mayor of London, Edmund Shaa. Shaa (pronounced and sometimes spelled "Shaw") played a minor but pivotal role in the Wars of the Roses by preaching a sermon in 1483 which claimed that Edward IV had already been betrothed to another woman at the time of his marriage to Elizabeth Woodville, and that Edward V was therefore illegitimate and had no claim to the throne.
Shaa appears as "Shaw" in Shakespeare's play Richard III.