This A4 size study, made in red wine, is that of a cloven skull on display in the ossuary at Sedlec, about 1hr 30mins drive from Prague. It is very likely this poor soul suffered a terrible death. Many of the people whose remains are kept in this ossuary died of plague, but not all. Several skulls in the chapel show signs of terrible wounds inflicted during the Hussite or 'Bohemian wars'. This skull seems one of the most horrific as one side of the face is missing allowing a view right into the back of the cranium.
When I first visited the ossuary or 'bone church' on a wet day back in 1993 I had the wisdom to arrive on a Monday. Nothing monumental is opened in this country on a Monday. I wandered around the graveyard and found a broken window that offered me a glimpse of the skeletal remains of an estimated 40,000 people that have decorated the interior of this chapel since 1870. Although I've visited several times since, this first glimpse through a broken window has never been surpassed for the weird scene it revealed in the heart of this otherwise typically sleepy Czech town.
Some of the history of the bone church can be read here...
Follow this link for a 3D VR tour of the church.