Against this backdrop of depressingly widespread corruption and cynicism, a religious movement known as the Pataria arose in the Archdiocese of Milan.  It was aimed at reforming the clergy and ecclesiastic government in the province.  Its members were called patarini, and its first leader was Landolfo Cotta.  He was also sub-deacon of the archdiocese.

When the archbishop Ariberto died, Landolfo was one of four candidates—all of them patarini—who were put forward by the Milanese clergy to succeed him.  Although it was customary for the emperor to accommodate the wishes of the local churchmen, Emperor Henry III chose instead to install Guido of Valete, a known simonist.

Landolfo Cotta responded to this reaffirmation of a cynical status quo by leading popular protests, in which the citizenry refused to accept the sacraments from corrupted priests.  Guido answered by sending assassins after him—including while he was praying in church.

Fortunately for Landolfo, their skill did not match their rottenness.  The attacks took their toll, though, and he eventually died of pulmonary complications.