Killian was an Irish monk. He was made bishop and then went to Rome with eleven companions. From there, he received permission from Pope Conon to evangelize Franconia (modern-day Germany). He was very successful! That is, until he converted a duke.
Killian had converted the Duke of Würzburg, Gozbert, who had married his brother’s widow Geilana. Killian told Gozbert that his marriage was not in line with the precepts of the Church (details on why are fuzzy) and so Gozbert planned to abandon his marriage to live in full communion with the Church. Geilana was enraged when she caught wind of Gozbert’s plan!
According to legend, while Gozbert was away on a military expedition, Geilana plotted against Killian and his companions Colmán and Totnan. Geilana sent her soldiers out to behead the three missionaries in the town square where they were preaching. She hoped this would put a stop to Gozbert’s plans to abandon their marriage and become Catholic. Spoiler alert: it didn’t.
At first, Geilana denied knowing what happened but then one of her soldiers went mad with guilt and told the truth. Geilana eventually went insane, also, and died shortly after. All that to say, don’t murder someone and then lie about it; it won’t end well for you.
Fun fact: Killian is the patron saint of rheumatism sufferers. Because why not.
Image courtesy of https://commons.wikimedia.org/wiki/File:San_Kilian.jpg