The basilica of St. Plechelm is a Roman Catholic church dedicated to the 8th-century Irish monk Saint Plechelm, whose festival on 15 July has been on the calendar of the medieval diocese of Utrecht ever since his canonisation in the 10th century.
The oldest parts of the existing building date from the middle and the second half of the 12th century, but the history of the church goes back to the 8th century, when the traveling missionary Plechelmus founded the first church on the site, the Silvesterkerk, initially dedicated to pope Silvester and sometime before 954 rededicated to Plechelmus himself (canonised after the elevation of his relics).
In 954, bishop Balderik of Utrecht founded a chapter in Oldenzaal and expanded and restored the 8th-century church, allowing the relics of Plechelmus used on his canonisation to be transferred to it. The current tower was erected around 1240. The church was enlarged in Gothic style in 1480s.References:
The Château d'Olhain is probably the most famous castle of the Artois region. It is located in the middle of a lake which reflects its picturesque towers and curtain walls. It was also a major stronghold for the Artois in medieval times and testimony to the power of the Olhain family, first mentioned from the 12th century.
The existence of the castle was known early in the 13th century, but the present construction is largely the work of Jean de Nielles, who married Marie d’Olhain at the end of the 15th century.
The marriage of Alix Nielles to Jean de Berghes, Grand Veneur de France (master of hounds) to the King, meant the castle passed to this family, who kept it for more than 450 years. Once confiscated by Charles Quint, it suffered during the wars that ravaged the Artois. Besieged in 1641 by the French, it was partly demolished by the Spaniards in 1654, and finally blown-up and taken by the Dutch in 1710. Restored in 1830, it was abandoned after 1870, and sold by the last Prince of Berghes in 1900. There is also evidence that one of the castles occupants was related to Charles de Batz-Castelmore d'Artagnan, the person Alexandre Dumas based his Three Musketeers charictor d'Artagnan on.
During the World War I and World War II, the castle was requisitioned first by French troops, then Canadian and British soldiers. The current owner has restored the castle to its former glory.