The paper, first, aims at describing the evolution and changing patters of political violence in Germany. This predominantly quantitative empirical overview will be mainly based on a large data set on protest events (derived from newspaper). It refers to West Germany from 1950 to 1989 and to the united Germany from 1990 to 2002. As a complement, also data from official reports on "extremism" will be used. The protest event analysis shows that, contrary to widespread assumptions, the proportion of violent collective protest out of all protest increased over time. Since the 1990s, this increase is mainly a result of right-extremist activities which are impressive in numbers of events but much less so in numbers of participants. Second, the paper develops several hypotheses about the underlying reasons for the increase in the aggregate and some of the changing patterns of political violence. These hypotheses draw on theories/concepts of relative deprivation, political opportunities, discursive opportunities and interaction effects. It is argued that three factors are crucial in causing different levels of political violence: (a) the presence or absence of "mediating structures" at the macro level between challenger groups and the established forces, (b) (a) the presence or absence of "mediating structures" between the moderate and the radical branches of each the political right and the political left, and (c) the strategies and tactics of policing of protest.