England's Reformation was brought about largely by King Henry VIII. The Act of Supremacy in 1534 finally broke the formerly Catholic churches away from Rome. Other than precipitating great physical damage to many churches, over the following six years, the Catholic Abbeys and Monasteries were forced to give up their lands and possessions to the King. The church of Watford was no exception.
At least four abbeys possessed lands in Watford parish: Sulby Abbey, Daventry Priory, the Priory of St Andrew, and most of all, St James Abbey. These holdings had been accumulated over the 12th and 13th centuries by gift mostly from the Ardern and de Watford families. In the year 1286, long after being given to St James, the church of Watford was dedicated by Oliver Sutton, Bishop of Lincoln from 1280 to 1299. Daventry Priory held lands in Murcott, St Andrew Priory held in Silsworth, while St James held the Rectory and certain farmlands in Watford, and more.
Watford's church and the advowson were possessions of St James Abbey. Indeed, St James's second largest benefactor, after Northampton Town itself, was Watford. While the advowson of the church remained with the Crown, the other possessions of St James were eventually given to favoured citizens by Henry VIII and Elizabeth I.