The period of forced residence of the popes at Avignon, France (1309-77)
These were hard-headed men of affairs - men who would not lightly embark on joyous ventures, or seek for an ideal San Grail; nor were the popes, doomed to the Babylonian captivity for seventy long years at Avignon, able to call down the spark from on high which should consume all earthly ambitions in one great act of sacrifice.
There is nothing in it to indicate that the author's standing-point is earlier than the Babylonian captivity.
He was the last of seven French popes in succession who had done so, and had perpetuated for seventy-three years what ecclesiastical writers are fond of terming "the Babylonian captivity of the church."
It appears, too, that a register of the population of each clan was kept during the Babylonian captivity and its totals were published on their return to Jerusalem.
They were, On the Liberty of a Christian Man, An Address to the Nobility of the German Nation, and On the Babylonian Captivity of the Church of God - the three primary treatises, as they have been called.