教派化（Konfessionalisierung）理論是德國歷史學者Wolfgang Reinhard以及Heinz Schilling兩位，在1981年提出的。這個理論試圖從社會史的視野，來檢討歐洲近代初期宗教改革期間，教會、國家、社會彼此之間的互動關係。教派化理論的重點是，無論是世俗權力或是教派勢力，它們都想要透過彼此積極而緊密的策略聯盟，建立一批又一批忠誠的臣民與信徒，以強化自己的實力。在教派化過程中，不僅神聖羅馬帝國陷於分裂，更因此出現歐洲特有的教派國家（Konfessionsstaat）型態。在宗教戰爭中，接受新教信仰的帝國領邦，試圖透過帝國公法／帝國國家法學的論述策略，來反擊舊教帝國勢力所提出分離主義與背棄帝國的攻訐。本文希望從教派化理論，來勾勒出近代初期促成帝國公法／帝國國家法學、乃至教派國家現身的歷史脈絡。

The conception of Confessionalization developed by Wolfgang Reinhard and Heinz Schilling in 1981 intends to analyze the early modern European social interaction between the religion, the state, and people. As the secular territorial states enlarges their power by the union with certain reformed churches, the Holy Roman Empire fell into the crisis of the separation. At the same time, the territorial states, including not only the Protestant, but also the Catholic, have all changed themselves into the confessional state in which state and church cooperates to discipline the whole society. Furthermore, some Protestant territorial states and cities encountered the orthodoxists’ war menace and the empire jurists’ criticism of separationism. In order to answer these questions, the Protestant territorial states took the “legalization strategies” constructing the new public law arguments to relieve the doubts concerning their legitimacy and loyalty to the Empire. This article will find out the historical conditions which make the emergence of “ius publicum imperii” and the confessional state possible.