The northeast area of the region, dominated by the massif of Monte Gargano (1,055 m), was largely unsuited for agriculture and abandoned to forests. To the south and west of the Gargano stretched the largest plain of peninsular Italy, the Tavoliere delle Puglie. Although it mainly consists of sands and gravels, the plain is also crossed by several rivers. In ancient times, the land was best suited for cereal cultivation and, above all, for the pasturage of sheep in the winter. The Ofanto river, one of the longest rivers of the Italian Peninsula, marked the southern border of the plain. Despite their name, the impervious Daunian Mountains (1,152 m), west of the plain, were strongly hold by the Hirpini, an Oscan-speaking Samnite tribe.