This place is, with Sainte-Ode and Pont d’Oye, the only metallurgy industry which a seigneury has been named after. Established in the beginning of the 15th century, the factory of Laclaireau was essentially working for the local market. One must know that waterways had seen very soon industries set up on their banks, which needed hydraulic force, charcoal and iron ore for its productions. The first castle of Laclaireau was built on the edge of the ponds that supplied the forges of the Lespine family. In 1664, the family bought the title and the seignieurial rights of Ethe. From 1666, Jean Poshet activated the forge and the blast furnace of Laclaireau. He owned many factories in the area and proceeded with the groupings (already... at that time). So, Laclaireau became Forge while Ruette received the blast furnace. In December 1775, Count Nicolas-Jean de Lespine was murdered in the castle. The factory then went to the Briey family. From 1776 to 1786, it exclusively worked for Weapons Factory of Charleville (now in the French Ardennes region). The castle and factories burnt down on the 17th of April in 1794 by the French troops. The forges were quickly reconditioned before decaying with the fall of Napoleon. All metallurgy activities stopped in 1822. It was in 1833 that Count de Briey took possession of the estate of Laclaireau. Successively Minister of Finances then of Foreign Affairs of King Leopold 1st and finally plenipotentiary Minister for Belgium with Tsar of Russia, he made the old castle razed to rebuild in 1872 the one we see now on the top of the hill.