Hemskeborn the Mad Priest

[Zapmeister]

The title hero with an entourage of about 50 madmen and flagellants, under AI Arcoscephale's banner, just attacked a province deep in my territory.

Hemskeborn is a level 2 priest with no other magic or items. Last turn, he was not adjacent to the province he attacked, which is a loooong way from the nearest Arco-held province.

So how did he get there?

EDIT: He's not stealthy either (although that wouldn't help since his troops aren't either).