The topic of this work is Josip Juraj Strossmayer and his influence in politics, culture and religion. As a political representative, he participated in the important Grand Parliament in 1861, as a member of the People's Party. He demands for the rights of Croatian countries and sees them as united. Strossmayer also wants the Croatian people to have the same rights as the Austrians and Hungarians. After the revision of the Croatian-Hungarian settlement in 1873, he slowly begins to leave politics. Unhappy with that settlement, but also with the politicians represented in that settlement, he feels the emptiness that leads him to deviations from the political scene. The influence of Strossmayer in culture represents one higher level. As a benefactor in Croatian countries, he works through the second half of the 19 century. It is called the father of contemporary education and culture, and the best example of cultural work is the Yugoslav Academy of Sciences and Arts, today's HAZU. He was elected as the sponsor of this institution, whose work has now been continued by the Croatian Academy of Sciences and Arts. Also, he is referred as the builder, so he decided to build Saint Peter's cathedral. The cathedral with its height and appearance represents the city of Đakovo. In religious subjects, Strossmayer had big influence on I Vatican Council. As one of the opponents of Pope's infallibility (against Pio IX), with his five speeches, he will remain in the annales of church history. He has received much praise, such as the best speaker of the I Vatican Council. He suggested the influence of bishops and priests on the Catholic people. Therefore, we can call him as a man who is ahead of his time, because it was one of the decisions II Vatican Council.