WILMINGTON, Delaware ― His garden stroll with Adolf Hitler left Alfred Rosenberg invigorated.

Rosenberg was already one of the most notorious and powerful Nazis, chief architect of ethnic cleansing policies and the man responsible for plundering billions of dollars of art from European Jews.

At the meeting in April 1941, Hitler spoke of a larger role. “Your hour has come,” he said, according to an account Rosenberg scrawled in his diary.

For nearly 70 years, the infamous diary, an unprecedented insider’s glimpse of the Third Reich, was lost or hidden. On Thursday, federal investigators said they had finally recovered it, following a trail that started at Nuremberg, Germany, once led through the Philadelphia suburbs, and ended this spring in Upstate New York.

“These 400 pages are a window into the dark soul of one of the great wrongs in human history,” John Morton, director of U.S. Immigration and Customs Enforcement, said at a news conference announcing the find.

Agents from Homeland Security Investigations seized the diary in April from a home in Amherst, outside Buffalo.

They declined to discuss many details of their investigation ― including who last had the document ― but acknowledged tracking the diary to a friend of a secretary who once worked for Robert Kempner, a U.S. war-crimes prosecutor.

The world knew about the diary, which covers Rosenberg’s life from 1934 to 1944, because prosecutors cited parts of it during the Nuremberg trials, in which Rosenberg was convicted and then executed in 1946.

But the complete document vanished after the trials, and was believed to have been among thousands of pieces of evidence Kempner smuggled out of Germany.

(MCT Information Services)