the income from the cities further strengthened krešimir's power, and he subsequently fostered the development of more cities, such as biograd, nin, šibenik, karin, and skradin. he also had several monasteries constructed, like the benedictine monasteries of (1060) and "st thomas" (c. 1066) in biograd, and donated much land to the church. in 1066, he granted a charter to the new monastery of st.mary in zadar, where the founder and first nun was his cousin, the abbess "čika". this remains the oldest croatian monument in the city of zadar, and became a spearhead for the reform movement. during the same year, he gave his nephew stephen trpimirović the office of duke of croatia, which designated him as his co-ruler and successor.