clement viii's fate was bound up with the ambitions of alfonso v of aragon. alfonso wished to negotiate for naples, and so gave clement support; his queen maria of castile, and the aragonese bishops supported martin v. in the summer of 1423 alfonso persuaded the republic of siena to acknowledge clement viii, thus securing recognition for the pope of the avignon line in the very city, pavia, which was part of the republic of siena, where the roman pope martin v had convened an ecumenical council of the church.