A special mass in Bulgaria's biggest cloister the Rila Monastery will mark the fifty-ninth anniversary since the death of King Boris III on Wednesday. In the monastery's church, where the late Bulgarian monarch's heart is buried, the monks will pray for his soul. A similar ceremony has commemorated King Boris on August 28 for the past years. He died suddenly after a meeting with Hitler and there have been speculations that he was actually poisoned by the Nazi dictator who wanted a more obedient Bulgaria.