Individual priests could, by various means, obtain a grant of a, "personal privileged altar".
This type of grant of the indulgence was not limited to a physical altar, as above, but traveled with the priest whenever, and wherever, he celebrated Mass.
Such a privilege was automatically granted by law to cardinals and bishops, and could be obtained by priests upon request or by undertaking the, "Heroic Act of Charity", a private commitment by the priest offering to God any indulgences he merited to be applied to the most needy souls in purgatory.
With the 1724 bull Omnium saluti of Pope Benedict XIII, a privileged altar could be permitted in every patriarchal, metropolitan or cathedral church.
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