I found this set in a bow window in the Castle Lodge, a Tudor building in Ludlow, alongside other pieces of German stained and painted glass:-
The person depicted is Jan of Leyden, an Anabaptist (that is, an extreme radical Protestant) who led a revolt which took over the city of Munster in western Germany in 1534-35. He proclaimed himself the successor to King David and looked to the imminent Second Coming of Christ. Eventually, after a siege, the Bishop of Munster regained control of the city, and Jan and two other Anabaptist leaders were tortured with red-hot pincers and then executed, "to show", in the words of H.G.Wells, "that decency had returned to Munster". The cages in which the Anabaptist leaders were confined can still be seen at the city's cathedral.
Jan of Leyden became a legendary figure: a name of horror to Catholics and moderate Protestants for long afterwards. More than 60 years later Ben Jonson, in his play "The Alchemist", referred to two Puritan characters as "my little John Leydens".
The inscription reads:
"IOHAN VA LEIDEN EY KONICK DER ...EDENDOPER
THO. MONSTER WAERHAFTICH ...OTER"
What does this mean? And why is this piece of glass in Ludlow? I have yet to find answers to these questions. Any help would be appreciated!
Postscript: I tried consulting Pevsner's volume on the buildings of Shropshire, but found that it dismissed the Castle Lodge in a single line. It's clear that none of his researchers ever set foot in the place!