Horne

The lords of Horne took their name from the village of Horn in Limburg. An Engelbert of Horne appears in twelfth-century charters and is regarded as the family's ancestor; kinship with the counts of Loon is suspected but unproven.

William I married the heiress of Altena in 1230, and the family built up lordships across the Meuse. Around 1300 Gerard I held Horne and Altena; his son William IV added Gaasbeek by marriage. Horn castle was the family seat.

In 1450 Emperor Frederick III raised Horn to an imperial county, but the senior line died out in 1540 and the title passed by adoption to the Montmorency family. Philip of Montmorency, count of Horn, was beheaded at Brussels with Lamoral of Egmond in 1568, and the county was handed to the bishop of Liège. A younger line, the princes of Hornes in the Spanish Netherlands, survived until 1826.