In late 1553 or 1554, Suleiman the Magnificent, the reigning Sultan of the Ottoman Empire, issued a firman (royal decree) formally denouncing blood libels against the Jews.
The Catholic Church denounced blood libels in the 1960s.
– Wikipedia on Blood libel against Jews
(Okay, yeah, there were popes who weren’t happy about it much earlier than that – memorably Sixtus IV, and I do appreciate how there were at least four of Pope Sixtus – but I think the Church as a whole never paid much attention to papal policy on the matter. The blood libel was all local politics.)