Probably around January of 897, Stephen VI ordered that the body of his predecessor Formosus be removed from its tomb and brought to the papal court for judgement.
Formosus was accused of transmigrating sees in violation of canon law, of perjury, and of serving as a bishop while actually a layman. Liutprand and other sources say that Stephen had the body stripped of its papal vestments, cut off the three fingers of his right hand used for benedictions, and declared all of his acts and ordinations (including his ordination of Stephen VI as bishop of Anagni) invalid. The body was finally interred in a graveyard for foreigners, only to be dug up once again, tied to weights, and cast into the Tiber.
You can read more details about the trial on Wikipedia.
There is also a painting there depicting the dead Pope during the trial.
This story made me thinking about the sanity of rulers at that time. Torture can be explained: they needed confessions, had to make an example, etc. But this? What was this bizarre game good for? According to the sources I read there was a public outcry even then after this shameful procedure.
I wonder if we are better these days? Or are there lots of people amongst us who wouldn't hesitate to take part in such trials if it wasn't against the law?