About this same time, Judah, the son of Jacob, took in marriage Sava, a woman of Canaan. By her he had three sons—Her, Onan, and Sela. Her was allied by concubinage to Thamar. On his death, Onan took his brother's wife; and he is related to have been destroyed by God, because he spilled his seed upon the earth. Then Thamar, assuming the garb of a harlot, united with her brother-in-law, and bore him two sons. But when she brought them forth, there was this remarkable fact, that, when on one of the boys being born, the midwife had bound his hand with a scarlet thread to indicate which of them was born first, he, drawing back again into the womb of his mother, was born the last boy of the two.
The names of Fares and Zarah were given to the children. But Joseph, being kindly treated by the royal governor who had obtained him for a sum of money, and having been made manager of his house and family, had drawn the eyes of his master's wife upon himself through his remarkable beauty. And as she was madly laboring under that base passion, she made advances to him oftener than once, and when he would not yield to her desires, she disgraced him by the imputation of a false crime, and complained to her husband that he had made an attempt upon her virtue.
Accordingly, Joseph was thrown into prison. There were in the same place of confinement two of the king's servants, who made known their dreams to Joseph, and he, interpreting these as bearing upon the future, declared that one of them would be put to death, and the other would be pardoned. And so it came to pass. Well, after the lapse of two years, the king also had a dream. And when this could not be explained by the wise men among the Egyptians, that servant of the king who was liberated from prison informs the king that Joseph was a wonderful interpreter of dreams.
Accordingly, Joseph was brought out of prison, and interpreted to the king his dream, to this effect, that, for the next seven years, there would be the greatest fertility in the land; but in those that followed, famine. The king being alarmed by this terror, and seeing that there was a divine spirit in Joseph, set him over the department of food-supply, and made him equal with himself in the government. Then Joseph, while grain was abundant throughout all Egypt, gathered together an immense quantity, and, by increasing the number of granaries, took measures against the future famine.
At that time, the hope and safety of Egypt were placed in him alone. About the same period, Aseneh bore him two sons, Manasseh and Ephraim. He himself, when he received the chief power from the king, was thirty years old; for he was sold by his brothers when he was seventeen years of age.
Source: Sacred History (New Advent)