Three Augustinian monasteries in Warsaw, Ciechanów and Rawa were established a hundred years after the foundation of the Order (1256), thanks to endowment of Siemowit III, the Prince of Mazovia. Mazovia had been an independent duchy until it was incorporated in the State of Poland in 1526. The three monasteries mentioned above belonged to three different dioceses located: in Plock (the Ciechanów monastery), Poznan (the Warsaw monastery) and Gniezno (the Rawa monastery). In the post-partitionment period the church and State organization of the region was changed. A peripheric location of Mazovia enabled the monks to get in touch with pagans, whom they converted to Catholicism. They also strengthened their beliefs as it was determined in the charter of foundation. The Augustinians ministered to their parishes, ran schools for the local communities and universities for the monks (Warsaw). They distinguished themselves by their attentiveness to gaining knowledge and education. In the post-partitionmenst period the Augustinians were engaged in cultivating the Polish language and national habits. They were the defenders of Catholicism until the annulment of the monasteries in 1864.