in Hohenems. Cardinal Hohenems is the first on the left; his cousin
Charles Borromeo is on the right. His uncle
Pope Pius IV made him a
cardinal deacon in the
consistory of 26 February 1561. On 10 November 1561 he was appointed legate to the Council of Trent and, on 27 December 1561, governor of
Fermo. In February 1566, he received leave to depart from
Rome to
Konstanz. He was also eager to introduce the Jesuits into the Diocese of Konstanz, and corresponded with the Jesuit General Alfonso Borgia on the subject, though the project was long in bearing fruit. He returned to Rome to participate in the
papal conclave of 1572 that elected
Pope Gregory XIII. In 1568, Marco Sittico bought a property in Rome that he immediately set about rebuilding as the
Palazzo Altemps, to designs by
Martino Longhi the Elder; he also built the
Villa Mondragone at
Frascati. He assembled a formidable collection of Roman antiquities and sculptures. He opted for the titular church of
Santa Maria degli Angeli e dei Martiri on 3 October 1577, for the titular church of
San Pietro in Vincoli on 3 October 1578, for
San Clemente on 17 August 1579 and for
Santa Maria in Trastevere on 5 December 1580. Sometime before 31 July 1589 he resigned the government of the Diocese of Konstanz. Because of illness, he resigned as legate in Avignon on 4 June 1590. He subsequently participated in the
papal conclave of September 1590 that elected
Pope Urban VII; the
papal conclave of October–December 1590 that elected
Pope Gregory XIV; the
papal conclave of 1591 that elected
Pope Innocent IX; and the
papal conclave of 1592 that elected
Pope Clement VIII. In November 1592, he became legate in
Viterbo. ==Death and legacy==