Background Suicide has become an increasingly concerning problem among soldiers in recent years. Previous research has hypothesized that media-related social contagion effects, termed “Werther effects,” may contribute to military suicide numbers. Unfortunately, there is limited empirical knowledge on such social contagion effects in soldiers. We contribute to the literature by investigating this phenomenon in the context of a specific historical suicide case, allowing us to provide a longitudinal assessment: Crown Prince Rudolf, heir to the Imperial throne of the Austro-Hungarian Empire, who died by suicide in January 1889. His death was a well-known news story that shook the monarchy to its foundations. Notably, soldiers of the late nineteenth century were an especially vulnerable portion of the population, proven by the fact that the Austro-Hungarian military had one of the highest suicide rates at the time compared to other European countries. Methods and results An interrupted time-series analysis, relying on annual military suicide rates between 1873 and 1910, indicated a significant increase in the suicide rate the year of Rudolf's death, a pattern consistent with a social contagion effect. In fact, time series analysis estimated that there were about 30 excess suicides per 100,000 population within the year of Rudolf's death. Additionally, we identified a substantial change in the trend after Rudolf's death, pointing to a long-term decrease in military suicide rates. The latter was not observed in the general population but appeared to be unique to soldiers. Discussion Although we are very careful when interpreting causal effects with our historical data, we discuss the latter finding by questioning whether a change in military culture, that is, the establishment of better conditions for soldiers in the aftermath of Rudolf's suicide, contributed to decreasing suicide numbers. Although tentative, these findings are also highly relevant for the study of military suicide today.