Year 1673 (MDCLXXIII) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar and a common year starting on Wednesday of the 10-day slower Julian calendar.

Jean-Baptiste de Lully (French pronunciation: [ʒɑ̃batist də lyˈli]; Italian: Giovanni Battista Lulli; 28 November 1632 – 22 March 1687) was an Italian-born French composer who spent most of his life working in the court of Louis XIV of France. He is considered the chief master of the French Baroque style. Lully disavowed any Italian influence in French music of the period. He became a French subject in 1661.

Lully, son of a working-class miller, was born in Florence, Italy. Lully had little education, but he learned basic techniques on the guitar, originally taught by a Franciscan friar of Florence. Later in France, he learned how to play the violin, and to dance. In 1646, he was discovered by Roger de Lorraine, the chevalier de Guise, son of Charles, Duke of Guise, and was taken to France, where he entered the services of Mademoiselle de Montpensier (la Grande Mademoiselle) as a scullery-boy and Italian-language teacher. With the help of this princess, his talent increased. He studied the theory of music under Nicolas Métru. It has been said that a scurrilous song on his patroness (the doggerel he set to music refers to a "sigh" she produced while at stool) resulted in his dismissal. It is far more likely that he did not want to moulder out in the provinces with the exiled princess.^{[citation needed]}