Then for seven months she lived with a pious woman named Lucina, and together they secretly helped persecuted Christians. Finally she was discovered and arrested. Her accuser was her neighbor Lucretius who desired to obtain possession of her lands. She asserted before the judge that she would never sacrifice to demons, because she was a Christian. As punishment, she was strangled in prison. Her friend Lucina buried her with her brothers in the cemetery ad Ursum Pileatum on the road to Porto.
Divine punishment soon overtook the accuser Lucretius, who at a feast was mocking the folly of the martyrs. A small child cried out, "Thou hast committed murder and hast taken unjust possession of land. Thou art a slave of the devil", who at once took possession of him and tortured him three hours and drew him down into the bottomless pit. The terror of those present was so great that they became Christians.
Pope Leo II (682-683) translated their relics to a church which he had built in Rome in honor of Saint Paul. Later the greater part of the relics of the martyrs were taken to the Church of Santa Maria Maggiore.
Saint Simplicius is represented in art with a pennant, on the shield of which are three lilies, called the crest of Simplicius; the lilies are a symbol of purity of heart. Saint Beatrix is portrayed with a cord in her hand, because she was strangled. Their feast day is July 29.