The title of Baron Montagu of Boughton was first created in 1621, in the Peerage of England, for Sir Edward Montagu, eldest son of Sir Edward Montagu of Boughton and grandson of another Sir Edward Montagu who had been Lord Chief Justice during the reign of Henry VIII. He was also the brother of Henry Montagu, later created Earl of Manchester, and of Sidney Montagu, ancestor of the Earls of Sandwich.
Their ancestor was one Richard Ladde, grandfather of the Lord Chief Justice Sir Edward, who changed his name to Montagu in about 1447. His descendants claimed a connection with the older house of Montagu or Montacute, Barons Montagu and Earls of Salisbury, but there is no sound evidence that the two families were related. A case has been made out for the possibility that the Ladde alias came from a division among coheirs about 1420 of the remaining small inheritance of a line of Montagus at Spratton and Little Creton, also in Northamptonshire (Sources:English Genealogy, Anthony Wagner). (Sources:English Genealogy, Anthony Wagner).
The third Baron Montagu of Boughton was created Earl of Montagu and Viscount Monthermer in 1689 and Duke of Montagu and Marquess of Monthermer in 1705. He had married in 1675 the Lady Elizabeth Wriothesley, daughter of the 4th Earl of Southampton and a descendant of the original houses of Montagu and Monthermer. The Dukedom, Earldom and Barony of Montagu all became extinct on the death of their son John, 2nd Duke of Montagu, in 1749. The next creation was in 1762, in the Peerage of Great Britain. John Montagu, styled Lord Brudenell, son of the 4th Earl of Cardigan and maternal grandson of the last Duke of Montagu, was created Baron Montagu of Boughton in 1762. This title became extinct on his death without issue in 1770.