How modern was the nineteenth-century law of neutrality (1776-1870)?

The law of neutrality evolved from 1776 to 1870, but not in a linear way. Enlightenment saw neutrality as an autonomous choice of a sovereign polity. The First League of Armed Neutrality (1780) and the Declaration of Paris (1856) can be seen as landmarks in the rise of the free ships/free goods-principle and the promotion of free trade. The French Revolutionary and Napoleonic Wars brought a regression. The British restrictive position before 1856 was starkly criticized. Even in the late 1880s, the lack of codification and unity in the law of neutrality was striking: national case law, criminal law and ad hoc neutrality declarations remained essential sources for individuals and states alike to interpret the seemingly candid and simple twin obligation of impartiality and abstention. This period also saw the birth of the malleable concept permanent neutrality, imposed or guaranteed by the European Great Powers.