The De Mercy family rose to increasing power during the Middle Ages in the region of what is now southern Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

, Lorraine and Luxembourg

Luxembourg

Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south...

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By the fifteenth century Jean de Mercy was lord of Clémarais (1422); in 1477, Roger de Mercy ("the Valiant") was appointed Captain and Provost of Longwy

Longwy

Longwy is a commune in the Meurthe-et-Moselle department in north-eastern France.The inhabitants are known as Longoviciens.-Economy:Longwy has historically been an industrial center of the Lorraine iron mining district. The town is known for its artistic glazed pottery.-History:Longwy initially...

 by Duke René II of Lorraine

René II, Duke of Lorraine

René II was Count of Vaudémont from 1470, Duke of Lorraine from 1473, and Duke of Bar from 1483 to 1508. He claimed the crown of the Kingdom of Naples and the County of Provence as the Duke of Calabria 1480–1493 and as King of Naples and Jerusalem 1493–1508...

. The family progressively expanded their domain, incorporating parts of Aix-sur-Cloie, Battincourt and Piémont. A castle named Claimaraix is mentioned in a document dated 3 March 1612, as a possession of Anne de Landres, widow of Jean de Mercy. By the sixteenth century they owned substantial land near Esch, including the castle at Mittenthal and the important mill at Bergem

Bergem

Bergem is a town in the commune of Mondercange, in south-western Luxembourg. , the town has a population of 1,474. Nearby at Lameschmillen is the confluence of the Alzette and the Mess. In the Middle Ages it belonged to the de Mercy family, together with the aforementioned mill and the castle at...

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The inheritance of Count Claudius Florimund de Mercy (1666-1734), Imperial field marshal, (born at Longwy in Lorraine) passed to the Counts d'Argenteau.

Important scions of the family

• Florimond Claude, comte de Mercy-Argenteau
  Florimond Claude, Comte de Mercy-Argenteau
  Florimond Claude, comte de Mercy-Argenteau was an Austrian diplomat.He was the son of Antoine, comte de Mercy-Argenteau, and entered the diplomatic service of Austria going to Paris in the train of Reichsfürst Kaunitz...
  
   (1727–1794), Austrian diplomat, son of Antoine, comte de Mercy-Argenteau, who arranged the marriage of Louis XVI to Marie Antoinette.
• Marie-Charles-Isidore de Mercy, 1736-1811, Bishop of Luçon 1775-1801; Archbishop of Bourges, 1802-1811
• Eugène Arnould Henri Charles François Marie, comte de Mercy-Argenteau (22 Aug. 1838-2 May 1888). Husband of the musician Marie-Clotilde-Elisabeth Louise de Riquet, comtesse de Mercy-Argenteau
  Marie-Clotilde-Elisabeth Louise de Riquet, comtesse de Mercy-Argenteau
  Marie-Clotilde-Elisabeth Louise de Riquet was the elder daughter of Michel Gabriel Alphonse Ferdinand de Riquet , created prince de Chimay 1834, for himself only, and Rosalie de Riquet de Caraman...
  
  , a collaborator with Franz Liszt
  Franz Liszt
  Franz Liszt ; ), was a 19th-century Hungarian composer, pianist, conductor, and teacher.Liszt became renowned in Europe during the nineteenth century for his virtuosic skill as a pianist. He was said by his contemporaries to have been the most technically advanced pianist of his age...
  
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