Leo II, also known as Leon II or Levon II, became the King of Armenian Cilicia from 1269/70 and was a vassal of the Mongols. Five of his 16 children by his highly regarded wife Keran (who later entered a monastery) became kings.
Leo II apparently died of arsenic but I can find no further information on this. The Armenian Wiki page on Leo II does not appear to have the answer (though google translate comes up with some strange translations, e.g. 'Mamluks' comes out as 'mammals').
- Murder. Although several of Leo II's relatives were later murdered - his sons Hethum II and Thoros III, his grandson Leo III - there was a clear motive in each of these cases. I can see no apparent motive for murdering Leo II, though. Nonetheless, arsenic had been commonly used as a poison since Roman times.
- Medical Treatment. Arsenic was used to treat "certain ailments" since at least the time of Hippocrates but I have not found any evidence of any ailments Leo II might have had.
- Environment, but I'm not sure how this could occur in medieval times as it is apparently rare even in modern times.
Was Leo II murdered by being poisoned with arsenic? If so, is it known who did it? If not, how did he die from arsenic?