How had revolutionaries spread their ideas …

After 1815 due to the fear of repression, many revolutionaries or liberal-nationalists went underground to avoid arrest
(i) They established many secret societies to train revolutionaries and spread their ideas.
(ii) They opposed monarchical forms of governments that were established after the Vienna Congress.
(iii) They fought for liberty and freedom and thought the creation of nation-state as a necessary part of their struggle for freedom.
(iv) Giuseppe Mazzini founded secret societies like Young Italy and Young Europe for the unification of fragmented Italy.
(v) Following Mazzini’s model, secret societies were set up in Germany, France, Switzerland and Poland.
(vi) Liberalism and nationalism brought revolution in many regions of Europe like the provinces of Ottoman Empire, Ireland, Poland besides Italy and Germany.