Quiroga founded the hospital-pueblo of Santa Fe (Mexico City), with his own money. This was his first attempt at building a Utopia on the model of Sir Thomas More. He converted many Indigenous to Christianity. He sat on the tribunal that ordered the president of the first Audiencia, Nuño Beltrán de Guzmán, to be returned to Spain in chains. Quiroga and the other "oidores" of the second Audiencia also conducted the trial of Juan Ortiz de Matienzo and Diego Delgadillo, oídores of the first Audiencia.