The Swiss syllabi ("Lehrplaene") are extensive documents published by the administration of the 26 counties ("Kantone"). They specify what has to be taught at public schools (i. e. the stipulate the subjects, the number of lessons, the topics etc.). Therefore, they are among the most important instruments to regulate the school system. My research project aims to trace the development of the Swiss educational system in the second half of the 20th century. How do the counties organize the education at public schools? Which subjects and which topics are taught, and what is considered to be important? I analyze the organisational structures which appear in the syllabi of the compulsory education (i. e. year 1 to 9) in the German speaking counties of Switzerland since 1950. During this period, most syllabi have been renewed every 5 to 15 years.My theoretical approach is Niklas Luhmann's system theory. I understand the syllabi as the programs of the educational systems. From this point of view, they have a similar position as legal regulations in the judicial system. A vital principle of Luhmann's theory used in my analysis is the concept of complexity reduction achieved by a differentiation of the system and the formation of subsystems. The results of my work can be illustrated by some statements based on the analysis of the syllabi of the primary schools in the county of Berne. The syllabi used for this analysis date from 1950, 1966, 1973, 1983 and 1995. Generally speaking, a lot of the shifts in the organisational structures in the primary school are less radical than they seem to be at first sight. Especially the structure of the topics shows a reMost of the changes in the organisational structure are embedded in a long-term context. If a subject gains or loses importance, it does so over a long period of time and in several steps. There is only a small number of abrupt shifts in the development of the organisational structures. In this development, there might be seen several periods. During the first period (1950s and 1960s), there is generally speaking "not enough school". The syllabi prescribe a minimal programme, but they make clear that a wider programme offered (and partially paid) by the communities would be desirable. So the school system is going to be expanded in a second period (1960s and 1970s). The number of lessons and the variety of subjects increase - a typical case of a differentiation (and expansion) of the system. But this development seems to overburden the pupils, now there is "too much school". In addition the new variety of subjects is criticised since this split would not allow a consistent education. Therefore the number of lessons and subjects is reduced again in a third period (1990s). Thus the system itself does not become less complex, since it is only the top level of the organisational structure (i. e. the subjects) which is simplified. Within the subjects, new organisational structures are established. Luhmann's differentiation of the system now takes place in a different, so to speak "vertical" way. Among the concrete changes of the school system of Berne since 1950, the most important are the identical syllabi for boys and girls (1983), the gradual increase of foreign language education (since 1950) and the introduction of new school duties and responsibilities (health education, traffic education, IT etc.). The gradual upgrading of optional subjects from an additional offer which is "nice to have", but not necessary, to an integral part of the pupil's individual curriculum is also an important development. For an international audience, both the theoretical approach and the development of the school system of a Swiss county might be of interest.