The principles were deliberately non-dogmatic, since the brotherhood wished to emphasise the personal responsibility of individual artists to determine their own ideas and methods of depiction. Influenced by Romanticism, the members thought freedom and responsibility were inseparable. Nevertheless, they were particularly fascinated by medieval culture, believing it to possess a spiritual and creative integrity that had been lost in later eras. The emphasis on medieval culture clashed with principles of realism which stress the independent observation of nature. In its early stages, the Pre-Raphaelite Brotherhood believed its two interests were consistent with one another, but in later years the movement divided and moved in two directions. The realists were led by Hunt and Millais, while the medievalists were led by Rossetti and his followers, Edward Burne-Jones and William Morris. The split was never absolute, since both factions believed that art was essentially spiritual in character, opposing their idealism to the materialist realism associated with Courbet and Impressionism.