The Fourth International Conference on the History of Mathematics Education was hosted by Academy of Sciences and University of Turin (Italy). About 50 senior and junior researchers from 16 countries met for four days to talk about one topic: the history of mathematics education. In total 44 contributions were presented. The themes were Ideas, people and movements, Transmission of ideas, Teacher education, Geometry and textbooks, Textbooks – changes and origins, Curriculum and reform, Teaching in special institutions, and Teaching of geometry. In this volume you find 28 of the papers, all of them peer-reviewed. Since the first international conference on the history of mathematics education, the aim has been to develop this area of research, to attract more researchers and provide new insights that stimulate further “digging”. It is therefore very pleasing that so many new young researchers joined the conference, presenting results from ongoing or recently finished PhD projects. This makes us confident about a prosperous future of this research area as we look forward to the Fifth International Conference on the History of Mathematics Education, to be held in Utrecht, the Netherlands, in September 2017. Previous international conferences on the history of mathematics education: 2009 in Garðabær (Iceland) 2011 in Lisbon (Portugal) 2013 in Uppsala (Sweden)