Although it could hardly be said that Ascanio Sforza (1455-1505) was the cause of the family's integration into the roman noble society, it should nevertheless be taken into account the fact that he was the first of a series of clergymen who, thanks to their political power, allowed the Sforza to reside in Rome, close to the Holy See.

In some cases, their position furthered the acquisition of real estate such as the palace used as the Cancelleria Apostolica (today the Palazzo Sforza-Cesarini).

Ascanio was not the first clergyman of the family and his career suffered many ups and downs, often connected with the Sforza Dukes of Milan. In 1479, when Ludovico became governor of Milan, Ascanio was allowed to return from his exile in Perugia, and in the same year he was appointed bishop of Pavia by Pope Sisto IV.

In 1480 he was again exiled to Ferrara by Ludovico himself because of his sympathies for the Ghibelline cause, but after the reconciliation (1482) Ascanio always remained by Ludovico's side, to look after his interests.

Between 1484 and his death in 1505, he became bishop of Novara, Cremona and Pesaro, and, in 1484, he was appointed Cardinal of St. Vito and St. Modesto.

In 1492, Pope Alexander VI (Rodrigo Borgia) appointed him Vice Chancellor of the Holy Roman Church.

The investiture was probably due to Ascanio's support of the pope on his election to the Holy Throne, that same year. Actually, the pope's attitude towards Ascanio and his family changed some time later into open hostility.

Moreover, in 1499, Pope Alexander allied with the King of France, thus contributing to the French occupation of the Duchy of Milan and the arrest of its Lord Ludovico, erasing him from the history of Italy.

Just like his brother, Ascanio was arrested, taken to France and imprisoned in the Borges tower, where he remained until the conclave of 1503.

It was thanks to Cardinal d'Amboise, who hoped to rise to the Holy Throne through Cardinal Sforza's support, that Ascanio was allowed to take part in the conclave.
  Rome welcomed back its cardinal with magnificence, and the people acclaimed him showing affection all along his way through the city. In his "Diary" the Burcardo describes the route from Porta del Popolo which led the cardinal to his destination, the Cancelleria Apostolica, through Via di Ripetta and Via Retta (the present Via dei Coronari), passing by the Church of St. Celso.

Ascanio held the position of Chancellor until 1505, when he also died from the plague that spread in Rome that year.

His body is buried in the Church of S, Maria del Popolo, as requested by Pope Giulio II, who ordered a tomb built appropriate to his rank.

The Mausoleum, by Andrea Sansovino, is one of the most magnificent in Rome, and is situated in the choir area, behind the main altar.