The use of original texts from History of Mathematics is a way to introduce the sources on which mathematical knowledge is based into the classroom. Choosing historical texts carefully can help students to develop their mathematical reasoning skills and to realize the humanistic aspects of mathematical knowledge through the understanding of the formation process of mathematical thinking. In this paper we present two problems drawn from four mathematical treatises from the 15th and 16th centuries. For the first one, we present three similar wordings drawn from the Arithmetica (1484) by Pietro Borghi, the Coss (1525) by Christoff Rudolff, and the Libro Primero (1552) by Marco Aurel, which concern the hiring of a worker. The second one is a situation that was posed by one student to another in the last book of the Arithmetica practica y speculative (1562) by Juan Pérez de Moya. Our aim is to analyse some aspects of the development of algebraic thinking through the mathematical activity of problem solving, implemented in the classroom. The analysis of the different mathematical procedures for solving these historical situations can encourage students to devise their own methods when faced with an unknown problematic situation.