Next, Wentworth surveyed the major Catholic landowners in Leinster for similar treatment, including members of the powerful Butler dynasty. Wentworth's plans were interrupted by the outbreak of the Bishops Wars in Scotland, which eventually resulted in Wentworth's execution by the English Parliament and civil war in England and Ireland. Wentworth's constant questioning of Catholic land titles was one of the major causes of the 1641 Rebellion, and the principal reason why it was joined by Ireland's wealthiest and most powerful Catholic families.