Liberalism—both as a political current and an intellectual tradition—is mostly a modern phenomenon that started in the 17th century, although some liberal philosophical ideas had precursors in classical antiquity and in Imperial China.[37][38] The Roman Emperor Marcus Aurelius praised, “the idea of a polity administered with regard to equal rights and equal freedom of speech, and the idea of a kingly government which respects most of all the freedom of the governed”.[39] Scholars have also recognised a number of principles familiar to contemporary liberals in the works of several Sophists and in the Funeral Oration by Pericles.[40] Liberal philosophy symbolises an extensive intellectual tradition that has examined and popularised some of the most important and controversial principles of the modern world. Its immense scholarly and academic output has been characterised as containing “richness and diversity”, but that diversity often has meant that liberalism comes in different formulations and presents a challenge to anyone looking for a clear definition.[41]

Continental European liberalism is divided between moderates and progressives, with the moderates tending to elitism and the progressives supporting the universalisation of fundamental institutions such as universal suffrage, universal education and the expansion of property rights. Over time, the moderates displaced the progressives as the main guardians of continental European liberalism.[17]