French iconographer of medieval sculpture and decorative arts. Cahier studied at the College of Saint-Acheul. He joined the Jesuit order, ordained as priest, in 1824. Cahier lectured at the Jesuit colleges in Paris, Brieg (in the Swiss Canton of Wallis), Turin, and in Belgium at Brugalette. In the pre-photography days, Cahier began "collecting" medieval monuments, noting their location and iconography with the idea of documenting the Christian (i. e., Roman Catholic) faith via art of the middle ages.

Architectural historian and crusader for the protection of French medieval monuments; harsh opponent of Eugène Viollet-le-Duc's restorations.

Medievalist, wrote important monograph on sculpture at Chartres. Katzenellenbogen (literally, "cat's elbow" in German) was the son of the jurist and bank director Albert Katzenellenbogen (1863-1942) and Cornelia Josephine Doctor (1870-1941), both assimilated Jews. His parents, intent on him pursuing a business career, sent him to England to learn the language at an early age. In Frankfurt, he received his Abitur from the Goethe-Gymnasium in 1920. Katzenellenbogen studied Law at Giessen, 1920-1923, receiving his doctor of jurisprudence in 1924.

Early historian of medieval Christian art. Willibald Sauerländer included Martin among the "pantheon of great [early] art historians" of medieval art whose numbers included Adolphe Napoléon Didron, Charles Cahier, Ferdinand Piper and Franz Xaver Kraus.