For anybody interested, this is what I wrote on another thread (with a little additional information).
This seems to have its origins on the question of the deportation of Hungarian Jews - in which case it’s both an overstatement of his ‘actions’ (he was just one of a number of people - the Allies, the Swedes etc - putting pressure on Horthy, who was also under considerable pressure from the fact that the Russians were in Poland and only a couple of months from invading Hungary itself) and just plain wrong in terms of the numbers - of Hungary’s 650,000 Jews (pre-war), 450,000 perished. Of the 750,000 Jews in wartime Hungary (boundary changes) over 400,000 had been transported by the time of the various protests.
It wasn’t exactly a brave move on the part of Pius, by the way, the Americans had been in Rome for a month.
Perhaps it’s another 800,000 Jews somewhere?