Celio Piccolomini was born in Siena in 1609. On 29 October 1656, he was
consecrated bishop by
Giulio Cesare Sacchetti,
Cardinal-Bishop of Sabina, with
Carlo de' Vecchi,
Bishop of Chiusi, and
Francesco Rinuccini,
Bishop of Pistoia e Prato, serving as
co-consecrators. He was named
Apostolic Nuncio to France on 15 November 1656 and served until 30 August 1663. He was made a cardinal on 14 January 1664. He participated in the conclaves that elected
Pope Clement IX in
1667,
Pope Clement X in
1670, and
Pope Innocent XI in
1676. He was named
Archbishop of Siena on 18 March 1681. He was the
principal consecrator of
François de Laval de Montmorency,
Titular Bishop of Petra in Palaestina (1658);
Bonaventura Cavalli,
Bishop of Caserta (1668); and
Vincenzo Maffia,
Bishop of Patti (1671). ==References==