The Sistine Chapel’s plain shell hides a conclave chimney and a painted sky
Built for Pope Sixtus IV between 1473 and 1481 where the ruinous Cappella Maggiore stood, the Vatican chapel is about 35 by 14 metres with a ceiling near 20 metres high. Outside it is almost bare; inside, side-wall cycles and Michelangelo’s ceiling and Last Judgment draw centuries of visitors—and still host papal elections.
Designed by Baccio Pontelli and built under Giovannino de Dolci, the chapel reused earlier proportions: length as the unit, divided by three for width and by two for height, with six windows per long side. A marble transenna by Mino da Fiesole, Andrea Bregno, and Giovanni Dalmata once split clergy and laity evenly, then shifted as papal households grew. The shallow cross vault first shone brilliant blue with gold stars by Piermatteo Lauro de’ Manfredi da Amelia—replaced when Michelangelo began the ceiling in 1508. Opus alexandrinum pavement still marks processional paths. On 15 August 1483, the Feast of the Assumption, Sixtus celebrated the first mass and dedicated the chapel to the Virgin Mary. Its primary role remains the Papal Chapel’s liturgy; a permanent choir keeps Allegri’s Miserere in repertoire.
Before Michelangelo, Sixtus’s team—Botticelli, Perugino, Pinturicchio, Ghirlandaio, Rosselli—finished Moses and Christ cycles in 1482, with papal portraits above and trompe-l’œil drapery below. Florentine painters arrived in spring 1481, likely as part of a Medici–papacy reconciliation. Under Julius II, Michelangelo painted the ceiling from 1508 to 1512; after the Sack of Rome he returned for The Last Judgment between 1535 and 1541 for Clement VII and Paul III. Henry Fuseli, who lived in Rome 1770–1778, still sketched an Ignudo about 1800, proof the nudes kept teaching artists for centuries.
Conclaves make the chapel a political theatre. Smoke from a roof chimney signals votes: white for a new pope (ballots burned alone), black for no two-thirds majority (ballots with wet straw), with chemical additives aiding color. The first Sistine conclave, 6–11 August 1492, elected Alexander VI. Since 1996, Universi Dominici gregis lodges cardinals at Domus Sanctae Marthae while votes stay in the chapel. Raised wooden floors protect marble and hide signal jammers; Paul VI abolished equalizing canopies when cardinal numbers forced double rows. Seagulls on the chimney during the 2013 and 2025 conclaves even became social-media symbols. Function and fresco remain inseparable.
Source: Sistine Chapel
