Dudley Alexander Sydney Cosby, 1st Baron Sydney (c. 1730 – 22 January 1774), was an Irish politician and diplomat.

Background

Cosby was the son of Pole Cosby, of Stradbally, Queen's County, and Mary, daughter of Henry Dodwell. Dudley Cosby was his grandfather.

Political and diplomatic career

Cosby was elected to the Irish House of Commons

Irish House of Commons

The Irish House of Commons was the lower house of the Parliament of Ireland, that existed from 1297 until 1800. The upper house was the House of Lords...

 as one of two representatives for Carrick

Carrick (Parliament of Ireland constituency)

Carrick was a constituency represented in the Irish House of Commons from 1614 to 1800. It returned two members.-Boundaries and Boundary Changes:...

 in 1763, a seat he held until 1768. In 1763 he was also appointed Minister Resident to Denmark, where he was to assist the aged Envoy Extraordinary, Walter Titley. He arrived in Copenhagen

Copenhagen

Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...

 in February 1764, but returned to Britain already the following year. In 1768 he was elevated to the Peerage of Ireland

Peerage of Ireland

The Peerage of Ireland is the term used for those titles of nobility created by the English and later British monarchs of Ireland in their capacity as Lord or King of Ireland. The creation of such titles came to an end in the 19th century. The ranks of the Irish peerage are Duke, Marquess, Earl,...

 as Lord Sydney, of Leix, Baron Stradbally.

Family

Lord Sydney married Lady Isabella, daughter of Thomas St Lawrence, 1st Earl of Howth, in December 1773. He died already in January the following year, when the barony became extinct. Lady Sydney died in October 1836.