context: The existing basilica was built by Pope Paschal I around 817 and, in general terms, has retained its original appearance. The three-nave basilica with an apse oriented to the northwest was already in the depths of the quarter, in the labyrinth of streets, on an artificial terrace, and therefore the entrance to the building was preceded by a staircase and an extensive square atrium with a quadport. The original cathedral of St. Peter was adopted as a model during construction. Paschal I transferred to the newly built basilica the relics of 2,300 martyrs from the Roman catacombs, including the “titular” saints Praxeda and Pudenziana.
question: When was the chapel of St. Zeno created in the Basilica of Santa Prassed?
answers.text: around 817