Did you know that the Pope in the year 1000 was the leading mathematician and astronomer of his day? Did you also know that he was the first mathematician in the Christian West known to use Arabic numerals?

In this video, Nancy Marie Brown, author of The Abacus and the Cross: The Story of the Pope Who Brought the Light of Science to the Dark Ages, explores a parallel universe, an alternate history of the Middle Ages, in which science was central to the lives of caliphs, bishops, kings, and even popes.