Saint Wistan, or sometimes Wigstan, was a king of the central British kingdom of Mercia. As is often the case with rulers of the dark ages, little is certain about Wistan. He was born in an undetermined year (relatively unreliable sources claim 835 C.E.) to Wigmund and Elflaeda, the former of whom was probably the sub-king of the Hwicce and the latter the princess of Mercia, being the daughter of King Ceolwulf I. It is possible, although not definite, that his siblings were King Ceolwulf II and Lady Edburga of the Gaini, who would later become the mother-in-law of King Alfred the Great.
Wistan's father Wigmund died at some point during Wistan's childhood, apparently of dysentery, so when Wiglaf, Wistan's paternal grandfather and current king of Mercia, bought the farm in 840 C.E., Wistan became the new ruler of Mercia. Wistan was something of a religious maniac, though, and chose to pursue a career in religion rather than a career in statecraft. While he was busy with his God stuff, his mother Elflaeda handled the throne as acting regent. The departed king Wiglaf left a brother, Bertwulf, and in the tradition of power hungry royal uncles (or in this case, great-uncles), this uncle started looking for a way to gain control of the kingdom. Before we go any further, it should be noted that Wiglaf was definitely related to the dead king Beornred, but his relationship to Wiglaf is much less certain, although the story makes a little more sense if their brotherhood is assumed.
The first tactic Bertwulf tried was to attempt a marriage of his son Bertric to Elflaeda. Wistan tore himself away from his studies long enough to expressly forbid this, however. The sources cite his religious dislike of incest, valid since Bertric and Elflaeda were probably cousins, although it's every bit as possible that Wistan knew that once Bertric and Bertwulf revved the engine on their way down the road to power he could easily become a bug splattered on their metaphorical windshield. Poor literary imagery aside, he refused to allow the marriage, and since he was still king, what he said went.
Bertwulf decided to send his son to talk with the king, ostensibly peacefully. However, when Bertwulf met the king at Wistanslow or Wistow, depending on whom you ask, he greeted Wistan with a kiss, followed by a sharp rap on the head with the shaft of his dagger. Bertric's servant then finished the job by putting a sword through Wistan. With the dirty work done, the throne was free for Bertwulf to take, which he promptly did. Some sources say that this took place later in the year 840, while others say that it was actually in 849 or 847, while still other, less reliable ones improbably mark the year as being 892. No matter which year, though, all sources apparently agree that the murder took place on June 1.
A shaft of light from heaven reportedly marked the location of Wistan's body in the water meadows of the River Sence (where a church stands today to commemorate his death) until it was found, whereupon it was buried at the Royal monastery at Repton in a Saxon pilgrimage crypt. That crypt is still there today, although the body itself was moved to Evesham Abbey in 1019 C.E. In art, he is depicted as a Saxon prince leaning on a sword. His feastday is, predictably enough, June 1.
Sources: http://www.britannia.com/bios/saints/wistan.html,
www.catholic-forum.com/saints/saintw07.htm,
users.erols.com/saintpat/ss/0601.htm,
http://www.stwilfs.freeserve.co.uk/gartree.htm