“Very few Jews know the story of how all 50,000 Bulgarian Jews were saved.
Not a single Bulgarian Jew was deported to the death camps, due to the heroism of many Bulgarians of every walk of life, up to and including the King and the Patriarch of the Bulgarian Orthodox Church.”
http://www.candlesholocaustmuseum.org/index.php?sid=53&pid=49
I think the Bulgarians were very good at protecting the Jews of Bulgaria proper, but not so good at protecting the Jews of the areas they annexed during the war (parts of northern Greece and southern Yugoslavia).