Lansdowne, Henry Petty-Fitzmaurice, 3rd Marquis of Lansdowne (1780–1863)

English Whig politician, a consistent supporter of the abolition of slavery, free trade, and Catholic emancipation.

Lansdowne was educated at Westminster School, Edinburgh University, and Trinity College, Cambridge. Entering Parliament in 1803, he joined William Grenville's short-lived ‘Ministry of All the Talents’ (1806–07), which abolished the slave trade in the British Empire. He assisted in the passage of the Reform Bill in 1832, and subsequently turned down the premiership and a dukedom. He became the 2nd Marquess of Lansdowne in 1809.