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.

The combination of health issues has kept the Pope from performing his public duties, including weekly prayers on Sundays, but his doctors have recently said he is alert, joking, and continuing to work, as well as reading messages from well-wishers around the world.