The coats of arms of the popes who ruled the Eternal City for centuries can be seen on buildings and monuments throughout Rome.
A papal coat of arms is easily identifiable, as the shield will be surmounted by the triregnum (triple tiara or triple crown)* and a pair of crossed keys.
*In 2005, Pope Benedict XIV elected to have a mitre instead of a triregnum and this practise was adopted by his successor, Pope Francis.
Pope Martin V: 1417-31 (Cloister of San Giovanni in Laterano)
Pope Nicholas V: 1447-55 (Aurelian Walls)
Pope Callixtus III: 1455-58 (Ponte Milvio)
Pope Pius II: 1458-64 (Sant' Andrea della Valle)
Pope Paul II: 1464-71 (Palazzo Venezia)
Pope Sixtus IV: 1471-84 (Palazzo della Cancelleria)
Pope Innocent VIII: 1484-92 (Via Lata)
Pope Alexander VI: 1492-1503 (Santa Maria Maggiore)
Pope Pius III: 1503 (Sant' Andrea della Valle)
Pope Julius II: 1503-13 (Palazzo della Cancelleria)
Pope Leo X: 1513-21 (Santa Maria in Domnica)
Pope Adrian VI: 1522-23 (Santa Maria dell' Anima)
Pope Paul III: 1534-49 (Palazzo Farnese)
Pope Julius III: 1550-55 (Palazzo Spada)
Pope Pius IV: 1559-65 (Porta Pia)
Pope Pius V: 1566-72 (Santa Maria sopra Minerva)
Pope Gregory XIII: 1572-85 (Via del Babuino)
Pope Sixtus V: 1585-90 (Palazzo del Laterano)
Pope Clement VIII: 1592-1605 (San Giovanni in Laterano)
Pope Paul V: 1605-21 (Fontana dell' Acqua Paola)
Pope Gregory XV: 1621-23 (Sant' Ignazio di Loyola in Campo Marzio)
Pope Urban VIII: 1623-44 (Fountain of the Triton)
Pope Innocent X: 1644-55 (Fountain of the Four Rivers)
Pope Alexander VII: 1655-67 (St Peter's Square)
Pope Clement IX: 1667-69 (Palazzo del Banco di Santo Sspirito)
Pope Clement X: 1670-76 (Palazzo Altieri)
Pope Innocent XI: 1676-89 (St Peter's Basilica)
Pope Alexander VIII: 1689-91 (Fontana dell' Acqua Paola)
Pope Innocent XII: 1691-1700 (St Peter's Basilica)
Pope Clement XI: 1700-21 (Fountain of the Pantheon)
Pope Innocent XIII: 1721-24 (Palazzo del Commendatore)
Pope Benedict XIII: 1724-30 (Santa Maria sopra Minerva)
Pope Clement XII: 1730-40 (St John Lateran)
Pope Benedict XIV: 1740-58 (Triclinium of Pope Leo III)
Pope Clement XIII: 1758-69 (Palazzo del Quirinale)
Pope Pius VI: 1775-99 (St Peter's Basilica)
Pope Pius VII: 1800-23 (Obelisk of Antinous)
Pope Leo XII: 1823-29 (Palazzo Gabrielli Borromeo)
Pope Pius VIII: 1829-30 (San Paolo fuori le Mura)
Pope Gregory XVI: 1831-46 (Palazzo del Quirinale)
Pope Pius IX: 1846-78 (Porta San Pancrazio)
Pope Leo XIII: 1878-1903 (San Lorenzo in Panisperna)
Pope Pius X: 1903-14 (Santa Prassede)
Pope Benedict XV: 1914-22 (Santi Giovanni e Paolo)
Pope Pius XI: 1922-39 (Vatican Museums)
Pope Pius XII: 1939-58 (Piazza Pia)
Pope John XXIII: 1958-63 (Nostra Signora di Lourdes)
Pope Paul VI: 1963-78 (Lateran Baptistery)
Pope John Paul II: 1978-2005 (Entrance to Vatican Museums)
Pope Benedict XVI: 2005-13 (San Paolo fuori le Mura)