 Humanist concern with probability was largely stimulated by attempts to clarify the relationship between rhetoric and dialectic. A second, but related, field in which probability-terms became important for humanists was the translation, recovery, and interpretation of ancient texts, such as Aristotle’s Topics or Quintilian’s Institutio oratoria. Yet the renewed attention to the texts of Cicero and Quintilian, or those of Aristotle’s Greek commentators, in the fifteenth century does not seem to have produced an immediate challenge to scholastic usages of probability. In general, the terms probabilis or probabilitas appear to have been less central for humanists than for scholastic (moral) theology and jurisprudence. Many humanists prolifically used the word probabilis, but some shunned it and spoke instead of worthiness of belief (credibilitas). This may often signal not much more than a predilection for the Latin of some ancient author. A contrast to scholastic usage can at best be expected from authors who intended to make a break with scholastic dialectic such as Lorenzo Valla and Rudolph Agricola (Mack 1993, 31, 146; Nauta 2009, 233; Spranzi-Zuber 2011, 65).