Today, football is the most popular sport in the world due to it's roots in human nature. The earliest trace FIFA (International Football Federation) recognizes is the chinese game cuju which dates back to cca 300 BC. Games similar to football can be found in other eras and civilizations such as ancient Greece, pre-Columbian Americas and Florence during the renaissance. Football in it's modern form is attributed to the British who, in 1864, were the first to establish modern rules of the game which are in place today, and who spread football in their colonies which, in the 19th century, comprised of one quarter of the world's population. Considering that, since then, more than 150 years have passed, different social and political events caused football to evolve as a game and as a social phenomenon. Philosophy of the game is in some cases closely related to social changes and it can be observed on three examples: Brasil and Argentina in South America and the Netherlands in Europe. With it's power to bring together such large masses of people, the importance of football clubs in the 20th century begins to rise as they become representatives of their communities. In some instances, oppressed social groups see their football clubs as the best representative they have. Types of identities can be split into: ethnic, religious, political, social class, regional and local. Their roots are in the percieved difference between supporters of one club and everyone else on the basis listed above, and are often coupled with violent behavior. Because of this violence, also called „hooliganism“ which became a social issue in the 1960's and lasts even today, it is important to study the psychology of a football fan and also give a sociological view of a supporter's group. An individual within a group experiences what psychologists call „deindividuation“, a loss of their personal inhibitions and acceptance of the norms of the group. Also, since an occasional experience of a risky situation is claimed to be essential for one's psychological and physical health, an individual uses violence as a way to fulfill that need. Football supporters and their rituals can be compared to religion as they include a number of special behaviors that can be found in religious life such as initiation of a supporter, myth, and taking part in a „mass“, a match, inside a „temple“, a stadium. However, not all football supporters are the same. The loudest and most committed among them create a group called „ultras“, who, other than violence, have other ways of expressing themselves: visual (flags, scarves and banners) and verbal (singing and chanting) expressions.