How did Founding Father Ben Franklin—who was decidedly not Catholic—come to play a role in the selection of the first Catholic bishop in the United States?
It all began in February 1776 when Franklin, Charles Carroll, and Samuel Chase were dispatched by the Continental Congress to Canada to convince them to join the 13 American colonies in rebellion against the British Crown. Franklin was fluent in French and a noted diplomat, Carroll was a wealthy Catholic who spoke French, and Chase was a Protestant who represented heavily Catholic Maryland. And accompanying them on their long, arduous journey from Philadelphia to Québec and Montreal was Carroll's cousin, Fr. John Carroll, a Jesuit priest.
Unfortunately, the Canadians treated the American delegation with suspicion and as traitors. The Bishop of Québec even forbade all priests and religious from even speaking to Fr. Carroll. To make it worse, the elderly Franklin became very ill during the trip, even fearing he wouldn't survive, and so he had to return home. Fr. Carroll accompanied him on the return trip, providing compassionate care the whole way.
Years later, after independence had been won, Pope Pius VI had an American problem, namely that Catholics in the new nation were still under the ecclesiastical authority of the Catholic bishop in London and thus they needed their own leadership. By this time, Franklin was the ambassador from the US to France and so he was approached by the papal nuncio for his opinion of any suitable candidates to become the first bishop of the United States.
Franklin spoke glowingly of Fr. Carroll, who nursed him back to health, and advanced his name as the right man for the job, which impressed the nuncio, and so in 1789, Pope Pius named John Carroll the first bishop of Baltimore with authority over Catholics in the whole United States of America.