Ivo Pilar (1874-1933) was a Croatian lawyer, politican and sociologist, but he also tried himself in many other cultural and scientific fields, such as literature, art criticism, historiography, psychology, anthropology, politology, philosophy etc. He first drew attention to himself in 1898, when he published an ideological-programmatic essay entitled „Seccesion― in Vienac, the most distinguished Croatian literary magazine of the time. That essay was published in the period of the strong conflict between modernist and traditionalist currents in Croatian literature and art. That conflict occured in other European countries, especially in Austria's capital Vienna, but in Croatia it gained specific characteristics because of the cultural and political context in which it happened. As described in the third chapter of the dissertation (the first chapter is an introduction, while the second is a reconstruction of Pilar's biography), Pilar became one of the ideologists of the younger generation, and throughout his whole life he held that modernist and an anti-clerical stance. Although born in Zagreb in an affluent and influental family, Pilar moved to Bosnia and Hercegovina in 1900 after finishing faculty of law in Vienna. Bosnia and Hercegovina was occupied by Austria-Hungary in 1878, but it remained formally under the sovereignity of the Sultan until it was annexed in 1908. The organizing of the political societies and parties was prohibited at the time, but despite strong limitations of public life, Pilar took part in founding the Sarajevo (Croatian) Literary Circle already in 1900. He also appeared in first open manifestations of Croatian national awareness in those provinces which were banned until then. The fourth chapter of the dissertation is dedicated to his work in Bosnia and Hercegovina in the first decade of the 20th century. It was in Bosnia and Hercegovina where Pilar understood that Greater Serbian propaganda, which was strongly supported by the governments of Serbia and Montenegro, as well as by the Serbian economiccultural and political elite from the Austria-Hungary, That idea was seeking to create a Greater Serbia and to supress all non-Serbs in order to secure the Serbian predominance. After realizing that he became convinced that the Croats must create an organization in order to confront that propaganda, and he thought that it was possible to achieve it by setting up a close cooperation between Catholics and Muslims, and at the same time, to harmonize their politics with the intentions of the ruling establishment, foremost of Austrian governing circles. Pilar was aware that the Hungarian nationalism, which sought to gain a higher degree of autonomy from Austrian domination, will easily find the way to cooperate with anti-Austrian Serbs. On the ground of his geopolitical and historiographic studies, he also reached a conclusion that Italian cooperation with Serbs is logical and natural, and that it endangers both Croatia and Austria-Hungary. 6 Because of that, he dedicated himself to the idea of Catholic-Muslim cooperation and worked systematically on the annexation of Bosnia and Hercegovina, which he considered as a first step in uniting those provinces with other Croatian lands. At the time many obstacles were in the way of the idea of Catholic-Muslim cooperation. The whole social life in Bosnia and Hercegovina was organized on confessional principles, and the Austria-Hungarian administration was displeased with the spreading of both Croatian and also Serbian national ideology. Because of that, the regime indirectly strengthened the confessional conception of political and social life, even after the failed attempt of creating a superconfessional national identity known as „Bosniak‖. At the same time, national ideologies in Bosnia and Hercegovina were shaped under the influence of the cultural fight (Kulturkampf) which occured all over Europe in the second half of the 19th century and lasted until first decades of the 20th. Pilar represented the opinion that the Croatian national idea is interconfessional, so that alone was enough to put him in a conflict with Josip Stadler, the influential and highly educated archbishop of Sarajevo. That conflict grew even larger with the founding of the Croatian Peoples Community (Hrvatska narodna zajednica) in 1906, which was the first cultural-economic organization of Croats from Bosnia and Hercegovina. The organization naturally grew into a first political party of Croats from these lands. Its founding was met with a frown from the authorites, as well as the defiance of archbishop Stadler who tried to impose a strong Catholic program on the organization. The archbishop's striving was partially motivated by the dispute between the Franciscans and the regular clergy which was installed in Bosnia and Hercegovina in 1881. That dispute led the Franciscans to strongly support the Croatian Peoples Community in its conflict with Stadler. After the failed attempt to gain predominance in the Croatian Peoples Community, archbishop Stadler founded the Croatian Catholic Association (Hrvatska katoliĉka udruga) in 1909/1910. That is why Catholic Croats were the only confessional group to enter the parliamentary elections divided, after the constitutional state in the country and a very complicated election system were instated in 1910. The Croatian Peoples Community won the majority of Croatian (in fact Catholic) votes, but even so, its leadership showed the will to back down in front of Stadler's demands. That was not the result solely of the dispute but also a result of the general political climate in Bosnia and Hercegovina as well as in Croatia. That development, followed by the occasional pro-Serb statements of his colleagues from the leadership of the Croatian Peoples Community, resulted in a great deal of Pilar's displeasure. Although he remained vice-president of the organization, he decreased his engagement within it and dedicated himself to his law practice and to scientific studies. Even though he once spearheaded the organization in the dispute 7 with Stadler, he soon showed the willingness to work with the archbishop of Sarajevo, once he saw it was in the Croatian national interest. The fifth chapter of the dissertation deals with Pilar's activity during the First World War. It was him who encouraged Stadler to try to intervene with the Pope Benedict XV. in 1915 in order to prevent Italy from entering the First World War. After that attempt failed, Pilar tried a series of moves to stop the breaking of AustriaHungary and to stop the creation of a Yugoslav state. His most important historiographic and political works and books were created during the war, The Yugoslav Question and the World War being the most important. It was printed in German language in Vienna in March 1918. In this dissertation special attention goes to that book which earned him a title of a key anti-Yugoslav ideologist. That work was considered dangerous literature in both Yugoslav states, and the book itself gave rise to legends which only demonstrated its value. Chapter six describes Pilar's views after the creation of the Kingdom of Serbs, Croats and Slovenians, when he was indicted in a show trial in 1921, and afterwards sentenced with a number of so-called associates even though he did not know most of them. Despite that, he continued to act in public, hold lectures and write articles in newspapers and magazines. In 1922 his voluminous psychological study came out which discussed specifically the issues of individualism, self-education and the future of Europe. A few years later Pilar became the president of the Sociological Society in Zagreb. His sociological views are motivated primarily with the need to confirm and legitimize his political conceptions, which was a trait of his studies in other fields, as well. At the time of Pilar's youth, the Yugoslav idea relied on a basis that Croatian and Serbian language are one and the same, and at the same time on another concept which was openly racist – that South Slavs are of the same race, which is basically superior to others. That racist concept and the worldwide interest in anthropologic and eugenic questions led Pilar to deal with anthropological research in some of his studies. Always loyal to the idea of Slavic cooperation, he did not doubt that the racial structure of the South Slavs is the same, and that Croats and Serbs are a part of the same race conglomerate. But even though his ideas regarding the formation of a nation and state changed over time, he remained permanently convinced that racial structure is of secondary importance in that process. In his opinion, political development, confession and the personal choice of the individual are of primary importance in forming a nation and state. In the second half of the 1920's, Pilar dedicated himself to the study of religious-cultural themes, mostly the phenomenon of the medieval Church of Bosnia (Crkva bosanska) which he calls the „Bogomilism―, even though he was aware that name is incorrect. The core of his efforts was to show that the Muslims from Bosnia 8 and Hercegovina were descended from Bogomils which are of Croatian origin. In that way he tried to strengthen the Croatian demands towards Bosnia and Hercegovina. That interest, in which Pilar shows the highlighted attempt to prove the influence of zoroastristic dualism on the old religion of Croats and Serbs, was also motivated by political reasons, therefore, his scientific contribution was not large. But, as the political situation grew more harsh, and the massacre of Croatian parliament members in the National Assembly in Belgrade (1928) led to the radicalization of the Croatian-Serbian conflict, Pilar spent the last five years of his life more engaged in the political turmoil. A series of his papers and memoranda in which he opposes revolutionary methods and radical decisions are written in that period. In them, he tries to offer the idea of reforming the Yugoslav state by gradually turning it into a federation. In that process, he thought that the Croatian lands would gradually unite and become stronger, and that the Croats would become more stronger economically, culturally, and politically. At the end of that process, they could obtain the nation's dream of an independent state in the right political time. In that direction Pilar tried to work with leading Croatian politicians of the time, and it also inspired his last book entitled Immer wieder Serbien (Always Serbia all over again) published under a pseudonym in Berlin in February 1933. Seven months later, Pilar was found dead in his house in Zagreb, and his death is considered unexplained to this day. Although after the end of the First World War Pilar never acted as an active politician, his lectures, studies and books still managed to have a strong intellectual influence on his contemporaries. That is why he can be considered one of the more important Croatian political ideologists of the first half of the 20th century.