Vasilissa was a Roman Christian girl who lived during the early 4th century. Born around 300 AD, she is remembered as a child martyr who maintained her faith despite intense suffering in Nicomedia. Following the death of Saint Anthimus, she was subjected to various tortures, including being exposed to fire and wild animals. Tradition holds that she remained unharmed during these trials, an event that reportedly led her persecutor, Alexander, to convert to Christianity.