What convinced Lucian wasn't, ultimately, that Lianelle couldn't remember her past. Sure, it was suspicious how all of her connections to anyone besides May had been cut or weakened, but that was only enough to push Lianelle so far. What convinced him that May was mind controlling his friend was Lianelle's lack of interest in being anywhere but by May's side. Lianelle didn't do that for anyone. She loved Katia with an intensity Lucian had hardly seen in any marriage, but she'd only visit Quiteria for a week at a time - never staying unless it was urgently required. When armies had been raised to fight the Magyar Lianelle had been there, but even then she'd ride off alone often, returning with news about how one village or another was now free. Seeing her relegated to a bodyguard and lover of someone she'd just met, with no apparent intention to ever leave, was... wrong. It wasn't Lianelle. 

And so, this is how Lucian finds himself digging a hole in an unremarkable forest in west Austria. Well, digging several holes - the landscape's changed enough in the last 1200 years that it's difficult to locate the exact spot where he and his men, victorious but weary, buried the Magyar's artifacts that they could not understand the purpose of.