Duchy of Florence in the context of "Pope Pius V"

Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei (/ˌɡælɪˈleɪoʊ ˌɡælɪˈleɪ/ GAL-il-AY-oh GAL-il-AY, US also /ˌɡælɪˈliːoʊ -/ GAL-il-EE-oh -⁠, Italian: [ɡaliˈlɛːo ɡaliˈlɛi]) or mononymously as Galileo, was an Italian astronomer, physicist, and engineer, sometimes described as a polymath. He was born in the city of Pisa, then part of the Duchy of Florence. Galileo has been called the father of observational astronomy, modern-era classical physics, the scientific method, and modern science.

Galileo studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion, and also worked in applied science and technology, describing the properties of the pendulum and "hydrostatic balances". He was one of the earliest Renaissance developers of the thermoscope and the inventor of various military compasses. With an improved telescope he built, he observed the stars of the Milky Way, the phases of Venus, the four largest satellites of Jupiter, Saturn's rings, lunar craters, and sunspots. He also built an early microscope.

Pope Leo XI (Italian: Leone XI; 2 June 1535 – 27 April 1605), born Alessandro di Ottaviano de' Medici, was head of the Catholic Church and ruler of the Papal States from 1 April 1605 to his death, on 27 April 1605. His pontificate is one of the briefest in history, having lasted under a month. He was from the prominent House of Medici originating from Florence. Medici's mother opposed his entering the priesthood and sought to prevent it by having him given secular honours, but after her death he eventually was ordained a priest in 1567. In his career he served as Florence's ambassador to the pope, Bishop of Pistoia, Archbishop of Florence, Papal legate to France, and as the cardinal Prefect for the Congregation of Bishops and Regulars. He was elected to the papacy in the March 1605 papal conclave when he was almost seventy. He almost immediately suffered from fever and died 27 days into his papacy.