Galileo Galilei of her life. Vincenzo was later legitimised as the legal heir of Galileo and married Sestilia Bocchineri. Although Galileo seriously considered the priesthood as a young man, at his father's urging he instead enrolled in 1580 at the University of Pisa for a medical degree. In 1581, when he was studying medicine, he noticed a swinging chandelier, which air currents shifted about to swing in larger and smaller arcs. To him, it seemed, by comparison with his heartbeat, that the chandelier took the same amount of time to swing back and forth, no matter how far it was swinging. When
Galileo Galilei references such as Psalm , , and 1 Chronicles which include text stating that "the world is firmly established, it cannot be moved." In the same manner, says, "the Lord set the earth on its foundations; it can never be moved." Further, Ecclesiastes states that "And the sun rises and sets and returns to its place." Galileo defended heliocentrism based on his astronomical observations of 1609 ("Sidereus Nuncius" 1610). In December 1613, the Grand Duchess Christina of Florence confronted one of Galileo's friends and followers, Benedetto Castelli, with biblical objections to the motion of the earth. According to Maurice Finocchiaro,