"Here's a Health unto His Majesty" is an English patriotic song or glee, now used as the regimental march of the Royal Army Medical Corps since 1948. Note the song is never "Here's A Health unto Her Majesty".
It dates from the reign of King Charles II, and was composed by Jeremiah Savile, a prominent teacher "for the voyce or viol" during the English Commonwealth and Restoration in London. The music was first published in John Playford's The Musical Companion of 1667, arranged for three voices; treble, tenor and bass, together with the lyrics for single verse:
"Here's a health unto His Majesty, With a fa la la la la la la, Confusion to his enemies, With a fa la la la la la la. And he who would not drink his health, We wish him neither wit nor wealth, Nor yet a rope to hang himself. With a fal lal la la la la la la la la, With a fal lal la la la la la."The song became popular again during the near-fatal illness of King George V in 1928, sometimes being sung in theatres before God Save the King.
References
Here's a Health unto His Majesty Wikipedia(Text) CC BY-SA