Pope Francis remained in critical condition Monday but showed slight improvement in laboratory tests and resumed some work, the Vatican said, including calling a parish in Gaza City that he has kept in touch with since the war there began.

Time-honored rituals, drafted and refined over centuries, allow for ritual mourning and provide order at a dramatic moment of transition.

Francis was also given blood transfusions, according to the Vatican, after blood tests revealed he was suffering from thrombocytopenia, meaning the platelet count in his blood was too low, a condition the doctors said is associated with anemia. Infections and medical treatment may lower platelet count.