During the pontificate of his brother, Benedict VIII, Romanus held temporal power in the city as consul and senator.

[5] Against the grain of ecclesiastical history, John XIX agreed, upon being paid a large bribe, to recognize the patriarch of Constantinople's claim to the title of ecumenical bishop.

John invited the celebrated musician, Guido of Arezzo, to visit Rome and explain the musical notation invented by him.

Negotiations being successful, the solemn word of the pope, Conrad and Rudolph was given with the witness of four archbishops, twenty bishops, and "innumerable multitudes of dukes and nobles",[7] suggesting it was before the ceremonies were completed.

John also enacted a papal bull endowing Archbishop Byzantius of Bari with the right to consecrate his own twelve suffragans after the reattachment of the Bariot diocese to Rome in 1025.

[9] Pope John XIX took the Cluny Abbey under his protection, and renewed its privileges in spite of the protests of Goslin, bishop of Macon.