Political map of Europe & the Mediterranean 31 August 1823 (Hundred Thousand Sons of Saint Louis): The Spanish Revolution of 1820 (Trienio Liberal) made King Ferdinand VII (Ferdinand VII of Spain) a virtual prisoner of the liberal revolutionaries and created unrest in the countryside. Eventually the continental powers of Europe agreed to a French intervention (Congress of Verona) and in 1823 France invaded Spain in support of the king, restoring his absolutist rule (Hundred Thousand Sons of Saint Louis).