The Iapydes (or Iapodes, Japodes; ) were an ancient people who dwelt north of and inland from the Liburnians, off the Adriatic coast and eastwards of the Istrian peninsula. They occupied the interior of the country between the Colapis (Kupa) and Oeneus (Una) rivers, and the Velebit mountain range (Mons Baebius) which separated them from the coastal Liburnians. Their territory covered the central inlands of modern Croatia and Una River Valley in today's Bosnia and Herzegovina. Archaeological documentation confirms their presence in these countries at least from 9th century BC, and they persisted in their area longer than a millennium. The ancient written documentation on inland Iapydes is scarcer than on the adjacent coastal peoples (Liburni, Delmatae, etc.) that had more frequent maritime contacts with ancient Greeks and Romans. The Iapydes had their maximal development and territorial expansion from the 8th to 4th centuries BC. They settled mostly in inland mountain valleys between Pannonia and the coastal Adriatic basin, but in disputation with southern Liburni they periodically reached also the northern Adriatic coast at Vinodol valley (classical Valdevinum). Their culture is largely nebulous due to the lack of material evidence. The Iapydes are believed to have been an Illyrian subgroup or mixed nation of Celts and Pannonian Illyrians with a strong Venetic element. A major scholar of the Japodi was archaeologist Branka Raunig. Origin and affinity The exact origin of early Iapydes is uncertain; archaeological documentation suggests mixed affinities to early Pannonii and Illyrians. The first written mention of an Illyrian tribe is from Greek writers from the 6th century BC. They are provisionally described by Strabo as a mixed race of Celts and Illyrians, who used Celtic weapons, tattooed themselves, and lived chiefly on spelt and millet; however, Strabo's suggestion of a mixed Celtic-Illyrian Iapydes culture is not confirmed by archaeology. Originally, Iapydes existed at least from the 9th century BC, and Celtic influence reached the region in the 4th century BC when Iapydes entered a decline. Archeological evidence of typical Celtic culture is documented only in the marginal contact zone of the Iapydes and the Celtic Taurisci along the Kupa river valley (now the Slovenian-Croatian border). Elsewhere, and especially in the main Iapydic area of the Lika highlands in Croatia, definite Celtic artifacts are scarce and explicable merely by commercial exchanges. Roman conquest Romans said of the Iapydes that they were a warlike race addicted to plundering expeditions,