The chapel, created by taking over the front part of the old sacristy, was ordered built by Niccolò Bensi in 1466 to hold the sacred head of Saint Catherine, the most important and valuable of her relics, which was brought to Siena after her death.

Catherine died in Rome on 29 April 1380 and was buried in the cemetery of Santa Maria sopra Minerva, but soon afterwards, because the cemetery was so damp, her body was exhumed and buried inside the church itself. On this occasion, Raymond of Capua, at the time General of the Dominican Order, asked and obtained from Pope Urban VI permission to detach the head from the body. The sacred relic was secretly taken to Siena in a silk bag which is still preserved in the Shrine of her house.

In 1385 Raymond informed the Consistory of the Republic of Siena that Catherine’s head was in Siena. Thus a solemn procession was organized, starting from the church of San Lazzaro outside Porta Romana, and moving towards the Basilica of San Domenico, where the relic was placed, enclosed in the copper bust which is now kept in the case to the right of the entrance into the chapel.

After Catherine’s canonization on 29 June 1461 by Pope Pius II, Niccolò Bensi, a member of a Sienese family, decided to have this chapel built to give the precious relic a worthy setting. The beautiful marble altar in the center of the back wall was carved in 1466 by . . .