Illyria is a land far away from The City. Vittori claims to have originated from Illyria, Garret notes that he only knew one other man from Illyria, and Vittori sounded nothing like him (Vittori claims he was exaggerating his voice for performance purposes). The Illyrian Traders is a business near the Canal in South Quarter.
Illyria is a nation referenced in Thief 2: The Metal Age. it was known for being an exporter of tea.