As a lawyer, he was the redactor of the codification of Polish criminal and civil law made at the behest of King Casimir the Great. He was also the author of the Wiślica and Wielkopolska statutes. In 1357, he convened a provincial synod in Kalisz, which passed 16 resolutions on the law and current affairs of the Church, including a decision to apply ecclesiastical punishments such as the interdict to anyone acting against the clergy or their landed estates.
Economic activity
He was an excellent administrator of the archdiocese entrusted to him. He launched a campaign to transfer old villages to German law, and founded many new ones, bringing colonists from Germany. He led the castellany of Łowicz to flourish. He got into many sharp border disputes with the bishop of Poznanń, especially in Mazovia. He led to the consolidation of the archbishop's estates by buying up more and more land.
Cultural activities
He built many churches and monasteries, and generously endowed those already erected. He rebuilt the Gniezno cathedral, founded churches in Kurzelów, Opatówek, created a collegiate church in Kamien Krajenski and in Uniejów and founded a Benedictine monastery there. He built castles in Łowicz, Uniejów, Kamień Krajeński and Opatówek, bishop's mansions in Gniezno, Kalisz, Wieluń and Łęczyca, and a brick church in his hometown of Skotniki. Around 1355, when Archbishop Jaroslaw Bogoria Skotnicki erected a Gothic brick castle on the site of the old castle in Lowicz, it soon became the residence of the archbishops of Gniezno. In 1359, Archbishop Jaroslaw Bogoria of Skotniki received Siemowit III, Duke of Mazovia, in Skierniewice. In it, the prince, whose state included Skierniewice, confirmed the archbishop's ownership of the area, and bestowed new privileges on the villagers. Archbishop Jaroslav Bogoria was probably the first of the archbishops of Gniezno to permanently reside in his seats in Lowicz and Skierniewice. During his reign, Skierniewice and the entire archbishop's estate began to record economic development and quickly grew into a fairly large settlement that could be transformed into a city.
References
^Janko, z Czarnkowa (1996). Kronika Jana z Czarnkowa (Wyd. 2 popr ed.). Kraków: TAiWPN UNIVERSITAS. p. 32. ISBN83-7052-989-5.
^Dunin, Teresa (1991). Polacy w Bolonii w pierwszej połowie XIV (streszczenie), "Rocznika Towarzystwa Naukowego Warszawskiego",. Warszawa.{{cite book}}: CS1 maint: location missing publisher (link)
