When, before the reintroduction of concelebration, priests frequently said Mass at a side altar while a public celebration was taking place at a nearby altar, the Congregation of Sacred Rites found it necessary to issue a prohibition against ringing a bell at the Mass celebrated at the side altar. The same rule was made even for a Solemn Mass celebrated at an altar other than that at which the Blessed Sacrament is publicly exposed, and allowed the ringing of the altar bell to be omitted when Mass was celebrated at the altar of exposition.