William Montagu, 2nd Earl of Salisbury, 4th Baron Montagu, King of Mann, KG (25 June 1328 – 3 June 1397) was an English nobleman and commander in the English army during King Edward III's French campaigns in the Hundred Years War.

[1] In 1348, Lord Salisbury, at this time married to the King's first cousin, was one of the knights admitted at the foundation of the Order of the Garter.

Lord Salisbury entered into the marriage in good faith, without knowing that Joan had already, at the age of twelve, secretly married Thomas Holland, just before the latter left England on crusade.

Lord Salisbury attempted to disrupt the proceedings by interfering with Joan's representatives and holding her captive so that she could not testify.

Following the findings of the inquiry, Lord Salisbury's marriage with Joan, Fair Maid of Kent, was annulled by the Pope in 1349.

Despite the fiasco of his marriage with a member of the royal family, Lord Salisbury rose rapidly in the ranks of the army upon the strength of his own competence.