Johannes Von Mengen III, Lord of Dalheim (Moingins dis li clers)

Parents. Forebears not securely recorded in the surviving registers of fourteenth-century Lorraine.

Spouse. Catherine de Gircourt.

Catherine, of the House of Haute-Pierre and by her paternal line a de Bauffremont, should not be treated as a minor spouse. Her marriage to Mengin Le Clerc appears to be the first great alliance in the Le Clerc story. Recorded through the Lorraine source tradition under the Girecourt byname of her mother's family, she is a sister of Philippin de Girecourt, écuyer (husband of Clémence de Pulligny, daughter of Jean de Pulligny), and is associated with Haute-Pierre, Toullon, Parroye and the Counts Palatine of Metz. Through her paternal Bauffremont line she carries one of the great baronial names of Lorraine and Champagne; through her maternal Girecourt-Haute-Pierre line she carries the local seigneurial network into which the Le Clercs married. The Bauffremont arms are given as: Vair, a bordure gules. The Gircourt arms recorded for her mother's family are: Gules, a lion argent, overall a chevron azure charged with three stag heads or, the shield semy of crosses pommety fitchy argent.

Children. From this union descend the entire documented Le Clerc, Leclerc and LeClaire pedigree of subsequent generations, beginning with their son Colin Le Clerc.

Mengin Le Clerc, also recorded as Moingins dis li clers, was born c. 1310 in Deyvillers, Duchy of Lorraine and stands at the beginning of the documented Leclaire history. He appears in the Lorraine charter tradition through the middle decades of the fourteenth century, reaching maturity in the years around the outbreak of the Hundred Years' War and the Black Death.

His earliest surviving act is dated 1355, when, in later maturity, he executed the sale of two inherited portions from the estate of the late Philippin de Girecourt, écuyer, in the place of Folz beneath the castle of Faucompierre, to Jean de Nomeny for 26 small gold florins. The transaction places him firmly within a documented world of property, inheritance, fortified places and local noble networks, and shows him already acting on estates inherited through his wife's family.

Mengin lived during the fourteenth century (c. 1310, c. 1360) in the Duchy of Lorraine, then an independent principality within the Holy Roman Empire. He is among the earliest documented ancestors of the Le Clerc family and occupies an important position in the lineage due to his marriage to Catherine de Girecourt, a member of an established noble house of Lorraine.

Mengin appears during the fourteenth century, a period shaped by plague, the Hundred Years' War, the schism of the Western Church and persistent political instability across the Duchy of Lorraine and the wider Kingdom of France. His documented span (c. 1310, c. 1360) coincides with the reigns of Ferry IV, Raoul and John I of Lorraine, and the French kings Philip VI and John II.

Mengin is the earliest securely identifiable ancestor of the House. With him the documented genealogical record of the Le Clerc, and therefore of the modern LeClaire, begins.

Mengin Le Clerc represents more than an early ancestor. He is one of the first individuals for whom surviving evidence demonstrates the family's place amongst the noble houses of Lorraine. His marriage to Catherine de Girecourt, combined with the later development of the Le Clerc de Pulligny branch, provides compelling evidence that the family already possessed recognised status within medieval society.

Rather than being the recipient of noble status through marriage, Mengin appears to have been a member of the same aristocratic milieu. His descendants would continue this tradition, ultimately producing the distinguished Le Clerc de Pulligny and later Le Clerc de Juigné branches that appear throughout French noble history.

Every subsequent generation of the House, the Sieurs de Pulligny, the Leclerc du Vivier, the Le Claire, Leclaire, Le Clair, Licklär and the modern LeClaire and Greenland-LeClaire, descends from Mengin Le Clerc.

Heritage summary: Mengin Le Clerc (fl. c. 1350) was a probable nobleman of Lorraine whose marriage to Catherine de Girecourt united the Le Clerc family with several established aristocratic houses of the region. Their descendants formed part of the later Le Clerc de Pulligny lineage, preserving a connection to the noble society of medieval Lorraine that would endure for centuries. Through this union, the family became linked to the houses of Girecourt, Pulligny, and Paroye, placing the earliest documented Le Clercs firmly within the hereditary nobility of eastern France.