It seems strange and morbid - well, that's exactly the point.
When looking at Christian art, it is very common to notice skulls next to a saint, or the saint may even be holding a skull, gazing into its hollow eyes. Why is that? Isn’t it a bit morbid?
Well, yes, that is exactly the point.
Skulls are featured in profiles of saints to emphasize their wisdom and constant awareness of their own mortality. Death was constantly in their thoughts and this motivated them to strive for perfection.
The Latin phrase memento mori (“remember death”) is one that the Church and many saints have used over the centuries to highlight this spiritual practice. It is a simple recognition that “thou art dust and to dust thou shalt return,” as we are told at the beginning of every Lent. This phrase reminds us that our lives on earth are very short and we do not know the day or the hour when Christ will come to call us home.
Some saints took this a step further and placed a skull on their desk, like Saint Gerard. According to Fr. John Bartunek, “Pope Alexander VIII even had the great baroque artist, Bernini, sculpt a mini, marble coffin for him when he was chosen as pope. He kept this on his desk to remind him that he would some day pass away and have to give an account to the Lord about how he lived his papal ministry.”
However much we want to escape it, death will come for us all. We have not found the “fountain of youth” that grants a reversal of age. Science has yet to create a pill that grants everlasting life on earth (and it never will).
Everyone dies. Saints remembered this simple fact and did not want to forget about it. They knew that God would judge them when they died and they did not want to appear before him empty handed.
It is healthy to dwell upon our own death and it is spiritually beneficial. If we do not have a healthy fear of death, we will forget our Christian duties on earth.
At the same time, it is also healthy to have a certain desire for death, realizing that if we live close to God, death will be a gateway to Eternal Life. For us death is both a curse and a blessing. It is punishment due to a fallen world, but is also a gift that speeds us on closer to perfect union with God.
Saints understood that and to recognize their wisdom, artists have painted them holding skulls or with skulls nearby.