The Middlesex Regimen (The Die-Hards) was an infantry regiment of the British Army. The 1881 Army Reforms merged several units to create county regiments. One of these was The Duke of Cambridge's Own (Middlesex Regiment), formed by merging the 57th Regiment and the 77th Regiment, which both had an existing affiliation to Middlesex and amalgamated in 1966 into The Queen's Regiment.