Query: How many other cities joined Strasbourg at the Imperial Diet of Augsburg in 1530?
Context: The Strasbourg Councillor Sturm and guildmaster Matthias represented the city at the Imperial Diet of Speyer (1529), where their protest led to the schism of the Catholic Church and the evolution of Protestantism. Together with four other free cities, Strasbourg presented the confessio tetrapolitana as its Protestant book of faith at the Imperial Diet of Augsburg in 1530, where the slightly different Augsburg Confession was also handed over to Charles V, Holy Roman Emperor.