|“||“Don't you recognize it'sa me, Mario!”||„|
During his life, Mario worked with his brother, Giovanni, also an Assassin, to gather the lost pages of Altaïr Ibn-La'Ahad's Codex, as well as fortifying and defending Monterrigioni to prevent invasions. Under his rule, Monteriggioni became a flourishing community again.
He was also responsible for the training of his nephew, Ezio Auditore da Firenze, into a fully-trained Assassin. After the training, he continued to provide guidance and advice, up to his death during the fall of Monteriggioni in 1500.
Mario was most likely born in Monteriggioni, Tuscany, and was the elder brother of Giovanni Auditore da Firenze, who was born when Mario was two years old. Mario came from a bloodline of notable Assassins, and therefore also became one, beginning his training at a young age.
When he was six years old, Mario played an important role in the Battle of Anghiari, where he alerted the condottiero Micheletto Attendolo to dust clouds over the road, which signalled a surprise advance on the Florentines by Milanese troops. Because of this, the attack was stopped, and the Florentines won the battle.
However, in contrast to helping the Florentines during that instance, Mario spent most of his life defending Monteriggioni from their persistent attacks on the town.
Ruler of Monteriggioni
In 1454, after Mario's younger brother Giovanni decided to move to Florence to pursue a career in banking, and after their father died, Mario became the lone ruler of Monteriggioni. Mario remained at the Villa Auditore, and exchanged letters with Giovanni to keep in touch. In one of these letters, Mario defended his decision to stay in Monteriggioni by writing that he "preferred fighting like a man, to filling out balance sheets." It is insinuated that he rarely saw the family after that. Under Mario's rule, Monteriggioni experienced a time of prosperity. Mario opened several shops and guilds in the city and greatly increased the city's defenses in order to withstand Florentine attacks. In 1454, he discovered a Florentine informant, Luciano Pezzati, living in Monteriggioni. Alongside his own mercenaries, Mario faced Pezzati and his men.
Mario dueled Luciano, barely defeating him, and had him dragged back to the Villa Auditore. From the Florentine spy, he discovered that the city was sending the condottiero Federico da Montefeltro to lead an attack on Monteriggioni. However, under Mario's leadership, the city was successfully defended and the invasion attempt ended in failure.
Eventually, Luciano Pezatti confessed the truth behind the siege, that the Florentines had attacked Monteriggioni in search of a mysterious artifact. Curious as to what this mysterious artifact might be, Mario gathered his architects and historians, eventually discovering that, years before, the city well had once been drained and excavated.