Vatican City, 30 April

Vatican post offices and selected collectors' shops this week started selling special stamps marking the period between Pope Francis' death and the election of his successor.

The so-called “sede vacante” stamps include an image used by the Vatican in official documents in periods between popes: two crossed keys but no papal headgear. They went on sale Monday and will only remain valid until a new Holy Father appears at the window of St. Peter's.

Until then, they can be used to send letters, postcards and packages. “With the election of the new pope, they lose the postal value, but the collectible value goes up,” Francesco Santarossa, who runs a collector's shop across from St. Peter's Square, said Tuesday.

The Vatican printed stamps in four face values: at 1.25 euros (USD 1.42), 1.30 euros, 2.45 euros and 3.20 euros. They carry the words “Citta del Vaticano” — Vatican City — and “Sede Vacante MMXXV” - vacant See 2025.

All bear a reproduction of the same image: three angels holding up a canopy shielding the symbolic papal keys against a background of white clouds.

The last time the Vatican issued stamps for the interregnum between popes was in 2012, when Benedict XVI broke tradition and retired. The issuing of sede vacante stamps dates from 1929.

Starting on 7 May, cardinals will gather to elect Francis' successor. It is not known how long the secret election will last.