- General relativity (Wikipedia)
General relativity, also known as the general theory of relativity and Einstein’s theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton’s law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations.
- Ferdinando de’ Medici, Grand Prince of Tuscany (Wikipedia)
Ferdinando de’ Medici (9 August 1663 – 31 October 1713) was the eldest son of Cosimo III de’ Medici, Grand Duke of Tuscany, and Marguerite Louise d’Orléans. Ferdinando was heir to the Grand Duchy of Tuscany, with the title Grand Prince, from his father’s accession in 1670 until his death in 1713. He is remembered today primarily as a patron of music. An excellent musician himself (sometimes called “the Orpheus of princes”), he attracted top musicians to Florence and thus made it an important musical center. Through his patronage of Bartolomeo Cristofori, Ferdinando made possible the invention of the piano.