Unlike Troy, all of Mycenae was never totally buried under tons of earth. Homer kept the idea of Mycenae alive throughout the ages too. Parts of it were buried but everyone knew it was there as the Lions Gate was always visible. Back in 1849 the Greek Archeological Society of Athens started the clearing of the court just outside the Lions Gate. They didn't find much and gave up or ran out of money or both. At the time, no one but Schlieman really believed in Troy or many of the things that Homer wrote about. Especially the Greek Archeological Society.
So when Schlieman came along they thought he had more money than sense and in general, pooh-pooh 'd and gave him a hard time with permits and so on. His first dig was in 1874, only lasted 5 days and yielded remains not considered important by the explorer. (That quotation was written by a Greek archeologist and typically calls him an explorer rather than an archeologist, most of whom are grave robbers or thieves anyway when you think about it.) There was another big scandal here in Greece not too long ago concerning the embezzlement of ticket receipts from ancient sites too. But I digress. The Greek government should have several statues of Schlieman but being aharistee (ungrateful) don't. Perhaps because it would make them look even stupider.
Heinrich came back however, two years later, in 1876, and better equipped, in only 14 weeks, discovered the Grave Circles or shaft graves of the royal families of Mycenae containing objects of gold, silver, terra-cotta and rock crystal. In fact he discovered more gold at this one site than has ever been discovered throughout all Greece in total! 14 KG of it!
Pictured above is what Schlieman called the Golden Death Mask of Agamemnon but turns out to be 300 years younger than the Trojan War epoch and is of an unknown noble of Mycenae.