In the Book of Genesis, a dove returned to Noah with an olive leaf.
After the Flood waters began to recede, Noah sent out a raven and then released a dove to test whether the ground had reappeared. The dove initially found nowhere to rest and returned to him. Noah waited seven days and sent it out again; this time it came back in the evening carrying a freshly plucked olive leaf.
A further seven days later, Noah sent the dove out once more, and it did not return. The sequence signaled that the waters were going down and that vegetation was visible again. The olive leaf therefore became a widely recognized symbol of peace and hope.
Genesis mentions both a raven and a dove, which causes a common mix-up. The raven is the first bird released, but the bird carrying the leaf is specifically the dove.