Collection of Sedi Vacanti Stamps from 1929-2013
Collection of Sedi Vacanti Stamps from 1929-2013: Pius XI, Pius XII, John XXIII, Paul VI & John Paul I

This complete set of sedi vacante stamps contains one from each election with a picture of each pope and his coat of arms.

Sedi Vacante is a Latin term meaning the seat is open.
It indicates the time between the death of one pope and the election of the next pope.