Challenge 151

The Diophantus Puzzle

Difficulty level:

History has kept little data about Diophantus. All that is known about him is found in the following epigram on his grave and written in the form of a mathematical riddle:

Walker! Here are buried the remains of Diophantus. And the numbers can show (miracle!) How long your life was, whose sixth part was your beautiful childhood. It was another twelfth part of her life when her face covered with hair. And the seventh part of its existence was a barren marriage. He spent another five years and was happy with the birth of his dear firstborn, whose beautiful existence lasted only half that of his father, who pitifully descended to the grave four years after his son's funeral.

How old was Diophantus when he died?