The balance-of-power idea became a crucial concept in the discourse of international affairs by the mid-seventeenth century. Nonetheless, the concept of balance of power was not even explicitly referenced in the Peace of Westphalia (1648). Instead, the legal principles of status quo ante and uti possidetis reigned supreme. Even though the balance-of-power principle was not mentioned in the Peace of Westphalia, it was often referenced during the negotiations and its implicit presence or practical balance of power was evident in the (...) treaties trying to reach stability in the inter-state system. Several alliances, concluded mostly against France and Louis XIV in the second half of the seventeenth century, implied the balance of power and, more specifically, the balance of sea power. The paper argues that the balancing process became less theoretical and more pragmatic as evidenced by interactive alliance treaties that established reciprocal responsibilities and numerical equilibrium. By the Peace of Utrecht (1713), the balance of power or the balance of Europe became a leading principle and it was referenced repeatedly in the treaties in different languages. The paper traces the balance-of-power idea from the diplomatic background to the diplomatic foreground as the idea moved from natural law to positive law. (shrink)