What is the name of XXX's country?
Lazio
The part of today's Lazio south of the Tiber river -- together with the present region of Campania immediately to the southeast of Lazio and the seat of Neapolis -- became Region I (Latium et Campania), while modern Upper Lazio became part of Regio VII - Etruria, and today's Province of Rieti joined Regio IV - Samnium.