Association football, also known as football or simply football, is a common team sport played by a spherical object between two competing teams of eleven players. It is so popular that it is played by more than 250 million people in more than 200 different countries and dependencies, which make it the most popular sport in the world. A game of football is a competition between two contrasting teams. The game is considered an art by many and football is the only sport where all players involved can be permanently eliminated when the game results are decided.
History of football can be traced back to as early as the seventh century BC in Germany. The game was used as a way to train military personnel and eventually the first international football tournament was held in Germany in the 7th season. Ancient Rome also played football and it became such an important sport that soldiers were trained in it during the Civil War. Ancient Chinese played football and it was even believed that football caused child birth.
The history of football can be clearly seen in the modern football shirt. A typical football shirt of this day contains a logo representing the team, which is usually either a club or a national team and contains a number printed on the left breast pocket. A common practice during tournaments is for teams to change their shirts after winning, to reduce the possibility of theft. Many manufacturers have also incorporated a football kit into clothing as a means of promoting their brand. This has lead to football shirts being made widely available to the general public and football has even become an Olympic sport, with football shirts being made and distributed to teams competing in the games.