This chapter focuses on the financial networks of the money changers in Renaissance Florence, particularly on the district of Santa Croce, in 1427. By analyzing tax declarations and records from the Catasto and Arte del Cambio, this chapter reconstructs the financial transactions and networks of 61 money changers residing in the area. Our study retraces how these professionals, initially currency exchangers, diversified into broader financial activities such as lending, banking, and trading in bills of exchange. The chapter also highlights the embeddedness of finance, politics, and commerce, showing how influential groups within the city used these financial networks to consolidate power, employing the Medici network as an illustrative case. Via analysis of their professional and political ties, this chapter underlines the role of money changers in the rise of high finance in Florence.