FR 8197 then FR 4437 at Fiumicino
Lisbon → Rome → Riga
Timetable, Rome time
13:20FR 8197 from Lisbon at the gate
06:00FR 4437 to Riga leaves the gate
16 h 40 apart on the timetable, overnight
FR 4437 leaves 16 h 40 after FR 8197 arrives on the timetable: more than half a day, so not a connection we count.