Owen Glendower led the last military struggle of the Welsh against the English crown for Welsh independence and nationalism. The failure of the Glendower rebellion established the supremacy of English rule over Wales. For six hundred years the status of Wales as a principality of the crown has not been seriously challenged. This paper will show how widespread the idea of "Welshness" was in 1400 and how much support existed for Wales as an independent nation. Welshmen sought to move from the status of a medieval, tribal principality to a position of an independent nation capable and ready to stand with other national in the world. The role of leadership that Owen Glendower assumed in the final rebellion against the English king, Henry IV, lifted him from a popular Welsh prince to an historical legend.