St. Quirinus is a Christian saint and martyr, believed to have lived during the early centuries of Christianity. He is often associated with the city of Neuss in Germany, where he is venerated as the patron saint. His feast day is celebrated on January 31. The historical details of St. Quirinus's life are somewhat unclear, but he is thought to have been a bishop who faced persecution for his faith. Many churches and places are named after him, reflecting his significance in Christian tradition and the enduring legacy of his martyrdom.