[1][2] The earliest images of St Paul were uncovered by a team led by Mazzei in 2009 in the catacomb of Santa Tecla (or Thekla).
[3] In 2010, Mazzei's team discovered images depicting the apostles John, Paul, Andrew and Peter in the catacombs of Santa Tecla.
[4] Mazzei led a seven-year investigation and restoration of Rome's catacombs of St Domitilla, which uncovered frescoes dating to around AD 360.
Using laser techniques similar to those at Santa Tecla, the team was able to penetrate the grime in order to reveal the frescoes, on the ceilings of two tombs of imperial grain merchants.
[5] The team discovered the images of the merchants accompanied by two saints, possibly the martyrs Nereus and Achilleus from the time of Diocletian.