Saint Efisius is a Christian martyr and the patron saint of the city of Cagliari in Sardinia, Italy. He is believed to have lived during the 3rd century and is often depicted in religious art wearing a soldier's armor, symbolizing his military background. His feast day is celebrated on May 15. According to tradition, Saint Efisius was a Roman soldier who converted to Christianity and was later executed for his faith. His story highlights themes of courage and devotion, making him an important figure in Sardinian culture and religious practices. Many churches in the region are dedicated to him.