Several centuries of Sisak history remain unexplained until the 9th century when it appeared in the history of Croats. At the beginning of the 9th century, Croats recognized the power of the Franks with which the Duke of Pannonian Croatia, Ljudevit Posavski, came into conflict. Sisak is chosen for a foothold in the resistance and the struggle for independence, Sisak, which confirms that the city still has preconditions for living and defence. With the establishment of the Diocese of Zagreb in 1094, Sisak and its surroundings became the property of the Bishop of Zagreb. At the time of Bela IV, Sisak was given the status of a town municipality with the city administration and the court, and by the beginning of the 16th century this town municipality was characterized by a relatively quiet period in which the inhabitants engaged in farming and livestock farming. This peaceful life is marred by the penetration of the Turks, who suffered a terrible defeat on June 22, 1593. The victory of the Christian army in defence of Sisak resonated across Europe so that Sisak became "antemurale Sisciense". During the 18th century, a quieter life favoured the development of trade and transport routes that affect the significance of Sisk. In it we find a church, a school, a doctor and a pharmacist, a grain warehouse and a grain fair. Cathedral of the Exaltation of the Holy Cross - Church of the Sisak Diocese, located in The Square of Ban Josip Jelačić, next to the archaeological park "Siscia in situ". Today's church was built in the first half of the 18th century. Century. On 05 December 2009, Pope Benedict XVI re-established the Sisak Diocese, led by Bishop Vlado Kolić, and declared the parish church of the Exaltation of the Holy Cross a cathedral.