For receiving with hospitable warmth these two gods in human guise, Deucalion, an old man, and his wife Pyrrha were spared, however. Zeus instructed his host to build an ark of oak, and store it well with food. When this was done, the couple entered the vessel and shut the door. Then Zeus "broke up all the fountains of the deep, and opened the well springs of heaven, and it rained for forty days and forty nights continually". The Bronze folk perished: not even those who fled to the hilltops could escape. The ark rested on Parnassus, and when the waters ebbed the old couple descended the mountain and took up their abode in a cave.[226] In Indian mythology the world is destroyed by a flood at the end of each Age of the Universe. There are four ages: the Krita or Perfect Age, the Treta Age, the Dwapara Age, and the Kali or Wicked Age. These correspond closely to the Greek and Celtic ages.[227] There are also references in Sanskrit literature to the destruction of the world because too many human beings lived upon it. "When the increase of population had been so frightful," a sage related, "the Earth, oppressed with the excessive burden, sank down for a hundred Yojanas. Suffering pain in all her limbs, and being deprived of her senses by excessive pressure, the Earth in distress sought the protection of Narayana, the foremost of the gods."[228] Manu's account of the flood has been already referred to (Chapter II). The god in fish shape informed him: "The time is ripe for purging the world.... Build a strong and massive ark, and furnish it with a long rope...." When the waters rose the horned fish towed the ark over the roaring sea, until it grounded on the highest peak of the Himavat, which is still called Naubandha (the harbour). Manu was accompanied by seven rishis.[229] In the Celtic (Irish) account of the flood, Cessair, granddaughter of Noah, was refused a chamber for herself in the ark, and fled to the western borders of the world as advised by her idol.[230] Her fleet consisted of three ships, but two foundered before Ireland was reached. The survivors in addition to Cessair were, her father Bith, two other men, Fintan and Ladru, and fifty women. All of these perished on the hills except Fintan, who slept on the crest of a great billow, and lived to see Partholon, the giant, arriving from Greece. There is a deluge also in Egyptian mythology. When Ra, the sun god, grew old as an earthly king, men began to mutter words against him. He called the gods together and said: "I will not slay them (his subjects) until I have heard what ye say concerning them." Nu, his father, who was the god of primeval waters, advised the wholesale destruction of mankind. Said Ra: "Behold men flee unto the hills; their heart is full of fear because of that which they said."