The other chapel is dedicated to Saint Barbara, and it is known as "within the Walls". Its site was originally occupied by a chapel dedicated to John the Baptist, but this was deconsecrated in 1575. The site was given to the Confraternity of St. Barbara in 1598, who built the existing chapel in the early 17th century, during the magistracy of Alof de Wignacourt and around the same time when the fortifications were being reconstructed. This chapel is annexed to the cathedral.