Ulster History Circle blue plaque unveiled in tribute to an MP often described as one of the most influential and distinguished British foreign secretaries.
Robert Stewart, Viscount Castlereagh and 2nd Marquess of Londonderry, was Chief Secretary of State for Ireland during the Act of Union in 1801 and is credited as being the architect of the Treaty of Vienna, which brought peace to Europe in 1815 after the downfall of the French Emperor Napoleon Bonaparte.
A plaque was unveiled in his memory at Ards Art Centre, Town Hall, Newtownards.
Among the guests who attended the event were Lady Rose and Peter Lauritzen from Mount Stewart Estate; The Lord Lieutenant of County Down, Gawn Rowan Hamilton; the Mayor of Ards and North Down, Councillor Karen Douglas; and High Sheriff for the County Down, Professor Mike Mawhinney.