Death and religion were larger preoccupations for 15th century Europeans than they are for us today, the ars moriendi is simply an easy example. The two themes walked hand in hand in virtually every Bosch painting, as well as many other Flemish masterworks and Durers more popular commissioned work.
The drawing itself shows how many religions, from buddhism and jainism to zoroastrianism, judaism and christianity/catholicism, worship their dead and spend much of their energies around rituals of preparing for death. Oftentimes, body parts too numerous to list or even entire corpses of dead saints or monks are worshipped, which I'm finding out is as much a buddhist phenomenon as it is a christian/catholic one. During the relic boom of the 14th century, hundreds of European churches claimed to possess the true remains of a number of saints. The shroud of Turin has no recorded history before the middle ages, and that artifact serves as a perfect example of what this piece looks at: religious objects which crystallize the fear of death and promise of life eternal. Some religions take this a step too far and have created churches/temples where, essentially, death itself is being worshiped in a very supplicating way.
