The 4th Duke of Argyll, born John Campbell in 1723, was a prominent Scottish nobleman and politician. He became the Duke in 1770 after the death of his father, the 3rd Duke. Known for his involvement in politics, he served as a Member of Parliament and held the position of Lord Privy Seal. The 4th Duke was also a significant figure in the Whig Party and played a role in various political reforms during his lifetime. He was a patron of the arts and contributed to the development of Inveraray Castle, the family seat, which remains an important historical site in Scotland.