FC Internazionale Milano, commonly known as Inter, was founded in 1908 as a branch of the Milan Cricket and Football Club (the club we call AC Milan today). It was a group of Swiss and Italians who were disappointed in the Italian dominance of the club, and instead founded FC Internazionale, an international football club.
The club had great success in the 1950s and 1960s and is one of Italy's most successful clubs throughout the ages. Inter shared their biggest glory days with Juventus: always more and more exciting matches between the two teams helped the creation of a big rivalry between the supporters. When the two teams are playing against each other, it's "Derby d'Italia" time, as for a long time it was this match that decided which team would win the league.
When one of the Milan teams wins the league, the supporters celebrate the league title outside the great cathedral of Milan, the Duomo. At the top of the Duomo there is a statue of the Virgin Mary who looks down on the new football masters. That's why the match between FC Inter Milan and AC Milan is called "Derby della Madoninna".
When Inter plays major games like these, the atmosphere is really powerful and no matter how it goes in the league or match, Giuseppe Meazza's "Curva Nord" offers unmatched "tifo" and powerful singing.
After several years of absence, Inter have managed to qualify to the Champions League, and have since then built a team with a lot of new talented palyers (Nainggolan, Martinez, Vrsaljko). Season 2018/19 will surely be an interesting one for Inter supporters.