Possible Clues:

• Its unusually valiant for this countryman
• European who could be valiant
• Volume in ancient language about a citizen of Riga?
• One from Riga of a valiant disposition
• That's enough to make one valiant from the Baltic
• Baltic national
• A language, possibly vital one
• From one of the Baltic states
• European valiant in battle
• National network involves the tube — first class return