#2 Benevento Calcio
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The original Benevento was founded in 1929 and they reached in Serie C fairly quickly. Despite performing well they never really went beyond being a solid outfit in the Italian third tier.
For 76 years, Benevento Calcio never saw the light of progress as a football team. Their teams repeatedly failed to make their presence be counted and the finances were most fragile. All of these factors combined to put the club out of business in 2005.
The Italian club, now known as Benevento Calcio, finally emerged to be on a path to progress when they won the Serie C2 in 2007-08 just two years after the refounding. A few years later the club solidified it's base and made a leap for Serie B.
In 2016-17, the club finished in the dizzying heights of 5th place in the Italian Serie B. This gave the club an opportunity to enter the playoffs for promotion, which they won and gained entry to the Serie A for the first time in their history.
A story which had taken 76 years but had been unsuccessful was now completed in 10 years. Though their season hasn't started very well, credit is due to the management of the club for believing that a club like Benevento could climb the walls of progress so quickly.