Charles Beauclerk, 1st Duke of St. Albans, served in the army of Emperor Leopold I of Habsburg and fought against the Ottomans.
This day in 1670 marked the birth of Charles Beauclerk, 1st Duke of St. Albans and illegitimate son of British king Charles II Stuart. King Charles actually elevated his six illegitimate sons to the rank of duke, which was (and still is) the highest aristocratic title in the UK. They were: the Duke of Monmouth, the Duke of Cleveland and Southampton, the Duke of Grafton, the Duke of Northumberland, the Duke of Richmond and Lennox, and the mentioned Duke of St. Albans.
By this granting of titles Charles II surpassed all other British rulers. It is important to mention Charles had no legitimate children and may have been trying to compensate for this by elevating his illegitimate heirs to high aristocratic positions.
Charles Beauclerk served in the army of Emperor Leopold I of Habsburg, and fought against the Ottoman Turks in the Balkans already at the age of 18. He participated in the siege of Belgrade, which the Habsburg forces took from the Ottomans in 1688.
Beauclerk married Diana de Vere, daughter of the last Earl of Oxford. They had many descendants, one of whom bears the title of Duke of St. Albans even today. Charles died in 1726, aged 56.