The livre tournois (French pronunciation: [livʁ tuʁnwa]; lit. 'Tours pound'; abbreviation: ₶ or £) was one of numerous currencies used in medieval France, and a unit of account (i.e., a monetary unit used in accounting) used in early modern France.
The 1262 monetary reform established the livre tournois as 20 sous tournois, or 80.88 grams of fine silver. The franc à cheval was a gold coin of one livre tournois minted in large numbers from 1360.In 1549, the livre tournois was decreed a unit of account, and in 1667 it officially replaced the livre parisis. In 1720, the livre tournois was redefined as 0.31 grams of pure gold, and in 1726, in a devaluation under Louis XV, as 4.50516 grams of fine silver.It was the basis of the revolutionary French franc of 1795, defined as 4.5 grams of fine silver exactly.