By what year had national football leagues been formed in nearly every country?
In the early days of association football, known simply as football or soccer, friendly matches (or "friendlies") were the most common type of match. However, since the development of The Football League in England in 1888, league tournaments became established, in addition to lengthy derby and cup tournaments. By the year 2000, national leagues were established in almost every country throughout the world, as well as local or regional leagues for lower level teams, thus the significance of friendlies has seriously declined since the 19th century.