In the early nineteenth century several foreign painters lived and worked in Romania and exerted a strong influence on young Romanian artists who, in turn, helped to train other artists of the nineteenth century. The spirit of nationalism and revolution that was sweeping Europe during that century involved Romanian artists as it did those in other countries under foreign rule. Art was a medium for expressing nationalist sentiments and the fight for self-determination. Most of the art of the period, therefore, represents historic and heroic subjects. Foremost among the revolutionary artists were Gheorghe Tattarescu and Theodor Aman, both extremely popular in their lifetime. Together, they exerted a great influence on the development of fine arts in Romania by founding the School of Fine Arts in Bucharest and by training young artists. Aman, in particular, is considered the country's first great modern painter. By far the most outstanding artist of the nineteenth century was Nicolae Grigorescu. His work remains extremely popular among Romanians, and his lyrical landscapes and scenes of Romanian life are well known abroad. The work of Stefan Luchian at the beginning of the twentieth century introduced to Romania some of the avant-garde styles that were appearing in European art elsewhere. Although he followed his predecessors in painting landscapes and rural subjects, he opposed their conservative style and introduced into his paintings a greater use of color than had been common. He also introduced social themes into his paintings by depicting the misery and poverty that were characteristic of the lives of most people. His best paintings, however, are flower studies, which bring out his love of color and of nature. Luchian's break with tradition and his use of color were followed by a number of artists, the most celebrated of whom was Nicolae Tonitza. These and other artists of the interwar period were greatly influenced by the impressionist and postimpressionist painters in Paris and Munich, where they studied. Their landscapes, flower studies, and portraits show the effective use of bright colors, which is considered characteristic of Romanian art.