The juro al quitar, a Castilian financial bond, was launched in 1489 as consequence of the royal treasury’s needs during the war of Granada. During the next decade, it experienced a profound reform and consolidation process. Economically, the Crown aimed to stabilize an instrument fully adjusted to its new enterprises abroad. Moreover, the ousting from the government debt markets of those who acquired their securities in 1489 produced a reduction of the risk of repudiation associated with the new consolidated debt; the juro, a Castilian late medieval instrument subject to the king’s ius commune.