Later he worked as civil servant at the Wieliczka Salt Mine under supervision of his paternal uncle Pietro de Franco.
[1] The royal preacher Piotr Skarga and the papal nuncio Simonetta participated in the procession, and witnessed Franco's action.
During his trial Franco urged the bishop "to stop deceiving people, and ordering to bow before idols, but to deliver the pure word of God ".
Franco's case was referred to the Pope, and Piotr Skarga personally interfered to obtain a death sentence.
According to Janusz Tazbir, Franco through his action wanted to change the passivity of Polish Protestants in face of triumphs and progresses of the Counter-Reformation.
[3] The execution took place in the vault of Vilnius Town Hall as the officials were afraid it could provoke outbreaks of violence and arson.
Soon after this execution, on 2 and 3 July, a religious riot broke out in Vilnius, during which the Calvinist church was plundered and burnt, and one minister was killed.
Afterwards, Franco was forgotten in Poland, but West-European Protestants (e.g. David Pareus), and Polish Brethren (e.g. Andrzej Lubieniecki), who stigmatized the Counter-Reformation, wrote about him.