This article is dedicated to the Order of the Holy Spirit in medieval Poland. The year 1528 is taken as the cut-off date, because at that time the Spiritualist churches (Holy Spirit and Holy Cross), the hospital and monastery buildings and the entire archive were burnt down as a result of the fire in Krakow. After the burnt buildings had been rebuilt, a change in the organisation of the hospital took place, which was significant not only for the Krakow house, but for all the Holy Spirit monasteries in Poland. In order to give a general overview of the Order of the Holy Spirit de Saxia, the place, time and purpose of its foundation are briefly discussed. Then the following problems are presented: the foundation of the Spiritualist houses in Poland, the endowment of the individual monasteries, the organisation and life in the Spiritualist monasteries in the light of the Rule, and finally the activities of the Spiritualists in Poland.