The diary of Nazi SS leader Heinrich Himmler was discovered filed in an archive in Russia.

The diary, actually a service calendar including dates, meetings and military decisions, was discovered earlier this year in the Russian Military Archive in Podolsk . It was filed under Dnewnik, which is Russian for diary, the Daily Mail reported.

The diary will be serialized in the German newspaper Bild beginning on Tuesday.

An entry in the 1,000-page diary in August 1941 revealed that Himmler, who was known to be squeamish at the sight of blood, almost fainted when the brains of a Jewish mass shooting victim at the edge of a pit outside of Minsk splattered on his coat, according to the Mail.

He writes in 1943 about witnessing the “effectiveness” of the diesel engines used to gas prisoners at the Sobibor death camp. That same day SS men threw a banquet in his honor, he recorded. He also calls for new guard dogs at the Auschwitz complex “capable of ripping apart everyone but their handlers,” according to the Mail.

In 1945, Himmler was captured by British soldiers in northern Germany, carrying falsified papers. He was recognized during his interrogation, which led him to bite down on a cyanide capsule hidden in one of his teeth. He died moments later.