Basilius

Basilius is a masculine given name, the Latin form of Basil. The name derives from the Greek Basilios, meaning “kingly” or “royal,” and has long been used by Latin-speaking writers, clergy, and rulers.

In ecclesiastical history, Basilius is associated with several saints and church leaders. The best known is Saint Basil the Great, a 4th-century bishop of Caesarea in Cappadocia and a major theologian and monastic reformer; in Latin, he is sometimes referred to as Basilius Magnus. Basil’s writings on the Trinity and monasticism influenced both East and West.

In secular history, the name appears in Latin and Greek chronicles for rulers such as Basil II (Basilius II, r. 976–1025), the Byzantine emperor who earned the epithet Bulgaroctonus, the Bulgar-slayer.

The form Basilius remained in use in medieval and early modern Europe, particularly within clerical and scholarly circles. Over time, the name largely gave way to Basil, Basilio, and other cognates in different languages. Today Basilius survives mainly as a historic or scholarly Latinized form of Basil and appears in onomastic lists, saints’ names, and Latin texts.