Each Pope has had his own coat of arms, generally related to those of his family.
This marble inlay in the floor of St. Peters Nave, is that of Innocent X Pamphili.
It shows a dove with an olive branch, which is seen on many other art works commissioned by the Pamphili Pope,
including the Four River's Fountain by Bernini, which is the centerpiece of Piazza Navona in Rome.