In 1684 he decided to take a step forward in his musical career, moving abroad to Bologna, which was the second most important city of the Papal State and one of the most active and prolific cultural centre in the whole of Europe. On the 27th of June 1684 he got admitted in the Accademia Filarmonica in Bologna, with the qualifications of “violinist” and “composer”. At that time, the aggregation had to be positively voted by 2/3 of the committee in charge; Giuseppe got accepted with 27 favourable and 3 dissenting votes. The entrance in this “society” represented an admission in the circle of the professional musicians, with an unquestionable degree that could open many possibilities for a young and talented performer and composer. This institution, founded in 1666 by Vincenzo Maria Carrati, rapidly gained such a prestigious reputation that being admitted as a member was consider an international coveted title. The Accademia's goal was to guarantee the highest level of professionalism of its memebers in order to defend its musical prestige. In fact, thanks to the privilege granted by the Pope, the Accademia had the authority to give to musicians the authorization for practicing the profession of chapel master in the churches of the city of Bologna and, furthermore, to supervise the musical activity in the city.
Once accepted as a professional musician in the musical Bolognese environment Giuseppe began his relationship with the most important musical insitution in Bologna, the Cappella Musicale of San Petronio, where he served as a sovrannumerario (extra musician, on call, for the special events that required a bigger orchestra) for two years.
It has been hypothized by Francesco Passadore that in these years he completed his training on the violin with Leonardo Brugnoli and Bartolomeo Laurenti, both violinists in San Petronio's orchestra (Brugnoli, native of Venice, is mentioned by Padre Martini also as the teacher of a young Arcangelo Corelli, when he was also serving in the same orchestra). According to Passadore it is also known that he perfected his contrapunctual and compositional skills with Giacomo Antonio Perti for a three-year period6.
On the 28th of September 1686 he got accepted as an official member of the orchestra of San Petronio, with the qualification of “suonatore di violetta” (viola player), as the successor of Geminiano Berosi for the position of tenor viola player, with a monthly salary of 12 lire.
One could only be appointed for a permanent position in that orchestra, after one of the members freed his position (in case of death, dismissal or abandonment by the musician himself). It was necessary then to submit a candidacy for the vacant position to the jury, formed within the Fabbriceria of San Petronio.
The Fabbriceria was a council of laymen, whose leader was a president appointed for life by the Pope, assisted by five other senators, who were each appointed for three years. The Fabbriceria was in charge of the administration and the coordination of all of the council's temporal affairs (allocating the budget for the different activities, hiring the maestro and the members of the Cappella). At the time of Torelli's admission the President was the Senator Marquis Girolamo Albergati, named by Pope Innocent XI, who resigned in 1696 in favor of his nephew Francesco Maria Albergati.
L'humiliss.mo O[rat]ore delle SS.rie Loro Ill:me Giuseppe Torelli, havendo presentito che sia vacato un luoco di sonatore di Violetta nella Capella di q.ta Insigne Basilica di S. Petronio ed bramando esso haver l'honore di servire in tal posto, ricorre per ciò alla somma begninità di loro SS.ri Ill:mi supplicandoli della loro protettione, et voto favorevole per conseguire il suo intento, promettendo servire con ogni pontualità [...]
[a tergo:] 28 Settembre 1686. Restò elletto per tutti li voti favorevoli in n. di 4: Caprara, Pietramellara, Orsi, Presidente.
The most humble servant of Their Illustrious Lordships Giuseppe Torelli, having being informed that one position of viola player got vacant in the Chapel of this distinguished Basilica di S. Petronio and desiring to have the honour to serve in that role, appeals to the highest begninity of Their Illustrious Lords for it supplicating for their protection, and favorable vote in order to achieve this intent, promising to serve with punctuality.
(On the back:) 28 Settembre 1686. He got elected with all votes favorable, in the number of 4: Caprara, Pietramellara,Orsi, President7.]
Giuseppe Torelli was then accepted with the positive unanimous vote of the four Fabbriceri in the jury. From that moment he served continously the Cappella, less regularly from the 1688 to the 1695 due to his activity as violinist in other cities, like Parma and Modena.