Vasileios is a Greek masculine given name, an alternate transcription of the Greek Βασίλειος (Basileios), most commonly rendered in English as Vasilios. Etymology The name Vasileios derives from the ancient Greek noun βασιλεύς (basileus), meaning "king" or "royal." Thus, its literal meaning is "royal" or "kingly." The name is built from two elements: basileus (king) and the adjectival suffix -ios. It is cognate with the name of Saint Basil the Great (Greek: Βασίλειος ὁ Μέγας, Basileios ho Megas), a 4th-century bishop of Caesarea and a key figure in early Christianity. Historical and Cultural Significance The name gained widespread popularity among Eastern Christians thanks to Saint Basil the Great. It was also borne by two Byzantine emperors, Basil I and Basil II, the latter known as the "Bulgar-Slayer." Through this dual religious and imperial heritage, Vasileios conveys a sense of nobility and spiritual authority. In modern Greece, several variant forms are in use: Vasilios, Vasilis, and Vassilis. The feminine equivalents include Vasileia, Vasiliki, and Vassiliki. Summary of Facts Meaning: "royal, kingly" Origin: Greek (via basileus) Type: First name (masculine) Usage Regions: Greece and Greek diaspora Notable Bearer: Saint Basil the Great Related Names: Vasilios, Vasilis, Basil, Vasil