Which impostor claimed to be the Earl of Warwick and was crowned in Ireland in 1487?

Lambert Simnel was the impostor who claimed to be Edward Plantagenet, Earl of Warwick, and was crowned in Ireland in 1487. His claim threatened Henry VII because the real Warwick was a Yorkist claimant and a grandson of the powerful Duke of York.

Simnel was a boy of humble and uncertain origins, trained by the priest Richard Symonds, who exploited the boy's resemblance to members of the royal family. Symonds first considered presenting him as Richard, Duke of York, one of the Princes in the Tower, but later promoted the more politically useful story that Simnel was the escaped Earl of Warwick.

On 24 May 1487, Simnel was crowned as King Edward VI at Christ Church Cathedral in Dublin, with support from Gerald FitzGerald, Earl of Kildare, and Yorkist forces backed by Margaret of York. The rebellion ended at the Battle of Stoke Field on 16 June 1487. Henry VII captured Simnel but spared him because of his age, eventually employing him in the royal household. The real Earl of Warwick remained imprisoned and was executed in 1499.