This article examines how one of the first initiatives in what now is known as "special education" came into existence in the historical context of the Netherlands. It focuses on the first private and autonomous institution for mentally retarded pupils, the so-called "School for Idiots", established in 1855 in The Hague by the Reverend Cornelis Elisa van Koetsveld (1807-93). The exploration into the history of this school concentrates on gender as an important factor in understanding the development of care for children with mental deficiencies. The aim is to show how a gendered expertise developed within the pedagogical practices of the institution and influenced the professional status of the participants in both care and education. The article also discusses some theoretical considerations that underlie the historical research. The historical case of the "School for Idiots" in The Hague is the central point of the second part of the article, in which both the participation of men and women in the institution and their professionalism are explored. The third and concluding part of the article relates the consequences of gendered professionalism to the rather slow development of special education as a professional domain in the Netherlands. (Contains 109 footnotes.)