Casian is a variant of Cassian, from the Roman family name Cassianus, meaning belonging to Cassius.
Casian is a variant spelling of Cassian, a name of Latin origin derived from the Roman gens Cassia — one of the ancient patrician families of Rome. The name traces to the Latin "cassus," meaning "empty" or "hollow," though ancient Romans understood naming pragmatically, and the name's resonance came more from the family's history than from its literal meaning. By the early centuries of the Common Era, the name had been transformed through the lives of notable Christians who bore it.
The most historically significant bearer is John Cassian (circa 360–435 CE), a theologian and monk who bridged Eastern and Western Christianity. After years in the Egyptian desert monasteries learning from the Desert Fathers, he founded two monasteries in Marseille and wrote the "Institutes" and "Conferences" — texts that profoundly shaped Benedictine monasticism and, through it, the entire tradition of Western Christian spirituality. Saint Cassian of Imola, an earlier martyr who died around 298 CE, is the patron saint of stenographers, adding a charming specificity to the name's hagiographic portfolio.
Casian — with its simplified single-S spelling — has a quietly elegant feel that suits both religious and secular contexts. In recent years, names ending in "-ian" or "-an" have enjoyed a renaissance (Dorian, Lucian, Fabian), and Casian fits naturally into that group: classical without being dusty, rare without being invented. It offers parents a name with genuine historical depth that will nevertheless require almost no explanation of origin.