God being offended by these things, and especially by the wickedness of mankind, which had gone beyond measure, had determined to destroy the whole human race. But he exempted Noah, a righteous man and of blameless life, from the destined doom. He being warned by God that a flood was coming upon the earth, built an ark of wood of immense size, and covered it with pitch so as to render it impervious to water. He was shut into it along with his wife, and his three sons and his three daughters-in-law.
Pairs of birds also and of the different kinds of beasts were likewise received into it, while all the rest were cut off by a flood. Noah then, when he understood that the violence of the rain had ceased, and that the ark was quietly floating on the deep, thinking (as really was the case) that the waters were decreasing, sent forth first a raven for the purpose of enquiring into the matter, and on its not returning, having settled, as I conjecture, on the dead bodies, he then sent forth a dove.
It, not finding a place of rest, returned to him and being again sent out, it brought back an olive leaf, in manifest proof that the tops of the trees were now to be seen. Then being sent forth a third time, it returned no more, from which it was understood that the waters had subsided; and Noah accordingly went out from the ark. This was done, as I reckon, two thousand two hundred and forty-two years after the beginning of the world.
Source: Sacred History (New Advent)