Was national security compromised by some PMs?

Following the death of the Roman Emperor Septimius Severus at Eboracum (modern York, England) while preparing to lead a campaign against the Caledonians, the empire is left in the control of his two quarrelling sons, Caracalla and Geta, whom he had instructed to make peace.<span class="mw-reflink-te...

Zhao Kuangyin declares himself Emperor Taizu of Song, ending the Later Zhou and beginning the Song dynasty.[2]

A strong earthquake strikes the Ionian coast of Sicily, causing tens of thousands of injuries and deaths, especially in Catania.[3]

Thirteen Years' War: The Secret Council of the Prussian Confederation sends a formal act of disobedience to the Grand Master of the Teutonic Knights, sparking the Thirteen Years' War.[4]

John Rogers is burned at the stake, becoming the first English Protestant martyr under Mary I of England.[5]

In Edo (now Tokyo), all but one of the Forty-seven Ronin commit seppuku (ritual suicide) as recompense for avenging their master's death.[6]