John XIX, born Romanus of the Tusculan family, was pope from 1024 to 1032. He was elected on 19 April 1024, ten days after the death of his brother Benedict VIII, continuing the dominance of the Tusculan house over the papacy. Prior to his election, Romanus had held senior secular offices in Rome, including those of consul and senator, and functioned as a civil leader within the city.

At the time of his election John XIX was a layman, an unusual but not unprecedented situation in this period. He was therefore required to be ordained and consecrated bishop before assuming the papal office. His retention of secular authority alongside his ecclesiastical role exemplifies the blending of civil and religious power characteristic of the Tusculan papacy, a period often criticised by contemporaries and later reformers for its reliance on aristocratic patronage and alleged simony ⓘ.

John XIX’s pontificate coincided with increasing tensions between the Eastern and Western Churches. He briefly considered recognising the Patriarch of Constantinople as ecumenical bishop, but withdrew in the face of opposition from within the Western Church. This episode reflects the growing doctrinal and jurisdictional strains that would later culminate in the Great Schism of 1054.

In 1027, John XIX attended the imperial coronation of Conrad II in Rome, reinforcing the alliance between the papacy and the Holy Roman Empire. During the later years of his pontificate he intervened in disputes over ecclesiastical jurisdiction and granted privileges to bishops and monasteries, actions that were sometimes criticised as examples of simony and part of wider concerns about corruption within the papacy at the time.​

​ John XIX also played a role in shaping Rome’s sacred landscape. In 1026–1027, he supported the translation of the relics of Saint Bartholomew ⓘ to the church of San Bartolomeo all’Isola, built on the site of the former Temple of Aesculapius. This act both enhanced the church’s spiritual prestige and reinforced papal authority over the city’s religious geography.

John XIX is generally regarded as a transitional figure of the Tusculan papacy, whose reign illustrates the extent of secular influence over the Church in the decades preceding the reform movements ⓘ of the later eleventh century.