Ecclesiastical Career
Landericus held both monastic and episcopal office. He is recorded as having taken over the direction of his father's monasteries around 660, receiving the monastery at Soignies from Vincent Madelgarius, and being succeeded there by Halidulphe about 675.
In the episcopate he is said to have first occupied the seat of Meaux, and to have been subsequently appointed the thirty-fourth Bishop of Metz, from which he is also known as Saint Landry of Metz.
A Family of Saints
Landericus belonged to a household unusually rich in venerated figures. His father, Vincent Madelgarius (also called Maelceadar or Mauger), born about 615 at Strépy, married Waltrude around 635; his mother Waltrude (c. 610–688) came from a wealthy noble family of Cousolre in northern France and became patron saint of Mons.
His three siblings were likewise venerated: Aldetrude, abbess of Maubeuge Abbey; Madelberta, who succeeded Aldetrude as abbess; and Dentelin of Mons, who died in childhood, about the age of seven. After Dentelin's death, Vincent and Waltrude agreed to separate and each pursue the monastic life. Vincent founded Hautmont Abbey around 642 and Soignies around 670, and was clothed in the monastic habit by Saint Aubert, Bishop of Cambrai, dying in 677; Waltrude withdrew to a cell and chapel near the oratory of Saint Ghislain.
Relics & Shrines
Landericus's relics were venerated at Soignies, with documented occasions of veneration recorded in 1269, 1406, and 1595. His shrine was opened on October 1, 1864, by Vicar General Charles-Joseph Voisin.
Veneration
Landericus is a pre-schism Western saint, principally commemorated in the Western calendar and venerated in the Roman Catholic Church, and included in the pan-Orthodox reckoning as a saint of the undivided Church. No article for him was found on OrthodoxWiki, and the OCA daily synaxarion for April 17 lists no commemoration under his name; no separate formal act of Orthodox glorification has been located.