The starting point for understanding the concept of monstra in Roman law is an etymological analysis of concepts such as prodigia, promonstra. The evolution of the latter term led to the disappearance of the prefix prod-, meaning anticipation. Monstra thus became the realisation of a miracle, that is, an event foretold by the gods, which also represented a warning and the necessity to ritually sacrifice a monstrosity in order to restore the pax deorum. In Roman law, on the other hand, the term monstra meant any being or behaviour that was contrary to the law of nature and, consequently, to civil law. This broadened the perception of the term, which originally had a more precise religious as well as legal meaning.

Medieval jurists succeeded in making the first attempts, which then made it possible to rank the degrees of guilt as follows: dolus – culpa – casus. Roman law addressed cases of unintentional crimes in a descriptive manner. For the manslaughter situation, they used the description of a weapon that escaped someone’s hand on its own and caused a someone’s death. A regulation of this kind has already appeared in the Law of the XII Tables. The topos of a weapon that itself escapes from a man’s hand was also used by early Christian writers. From there it made its way into medieval compilations of canon law.

The interwar period (1918—1939) was an intensive stage in the development of Polish universities. The resumption of the operation of Polish universities began with Poland’s regaining of political independence. Unfortunately, law students at the University of Warsaw initially had no proper Roman law textbook. For this reason, the lecture scripts (Pl. skrypt) and revision textbooks (Pl. repetytorium) that were being created as early as the 1920s played an important role in the process of teaching Roman law. Particularly noteworthy is an anonymous Roman law revision textbook published in Warsaw in 1924 and 1925, signed only with the initials J.L. The identity of its author has never been established, and for some time this was the only textbook available for law students in Warsaw. Admittedly, revision textbooks were a poor substitute for proper textbooks; however, due to prolonged lack of a Roman law textbook, the question arises as to their actual role in the interwar period.

Criminality in 20th-century Poland is an extremely interesting issue. World War II and the period of communism led to a profound transformation of Polish society, which also influenced broadly understood criminality (including political crimes). While studying twentieth-century history of criminality, researchers encounter numerous and considerable challenges; chief among them are: legal limitations in the access to sources and poorly preserved sources. Despite these and other obstacle, historical research, including historical criminology, may contribute to the deepening of the knowledge about Polish society in the 20th century.