[3] Trained in jurisprudence, Borghese was made Cardinal-Priest of Sant'Eusebio and the Cardinal Vicar of Rome by Pope Clement VIII.

His insistence on ecclesiastical jurisdiction led to conflicts with secular governments, notably with Venice, which resulted in an interdict on the city in 1606.

Pope Paul V's diplomacy also strained relations with England, as his actions were perceived as undermining moderate Catholics in the country.

In Rome, he financed the completion of St. Peter's Basilica, improved the Vatican Library, and restored the ancient Roman aqueduct Aqua Traiana.

Pope Paul V established the Banco di Santo Spirito in 1605 and is also known for fostering the rise of the Borghese family through nepotism.

[4] In June 1596 Camillo was made the Cardinal-Priest of Sant'Eusebio and the Cardinal Vicar of Rome[4] by Pope Clement VIII, and had as his secretary Niccolò Alamanni.

[7] In 1618, a Decreto de Nuestro Sanctissimo Padre el Papa Paulo V. en favor dela Immaculada Concepción dela Sanctissima Virgen Madre de Dios y Señora Nuestra (Decree of our most holy father Pope Paul V in favor of the Immaculate Conception of the blessed Virgin Mary,..) was published in Lima, Peru.

Venice passed two laws obnoxious to Paul, one forbidding the alienation of real estate in favour of the clergy, the second demanding approval of the civil power for the building of new churches.

When this was refused, the Pope threatened an interdict on account of the property laws and the imprisonment of ecclesiastics, which threat was presented to the Senate on Christmas 1605.

The Venetian position was ably defended by a canon lawyer, Paolo Sarpi, who extended the matter to general principles defining separate secular and ecclesiastical spheres.

Masses continued to be said in Venice, and the feast of Corpus Christi was celebrated with displays of public pomp and "magnificence", in defiance of the Pope.

In September 1607, after unsuccessfully attempting to lure Father Sarpi to Rome, the Pope responded by putting out a contract on his life.

Stabbed three times with a stiletto,[11] Fra Sarpi somehow managed to recover, while the assassins found refuge in the Papal States.

His letter of 9 July 1606 to congratulate James I on his accession to the throne was three years late and seemed to English eyes merely a preamble to what followed, and his reference to the Gunpowder Plot, made against the life of the monarch and all the members of Parliament the previous November, was unfortunate for the Papal cause, for Papal agents were considered by the English to have been involved (the effigy of Pope Paul V is still burnt every year during the Lewes Bonfire celebrations).

The letter received enough circulation to be referred to in one of James's theological essays (1608), and Bellarmine was soon fencing in a pamphlet exchange with the king of England.

He restored the Aqua Traiana, an ancient Roman aqueduct (named after him Acqua Paola), bringing water to the rioni located on right bank of the Tiber (Trastevere and Borgo) using materials from his demolition of the Forum of Nerva.