 There, he argued that the 1829 Treaty of Adrianople had loosened the Danubian Principalities from the constricting influence of long Ottoman domination, producing the fundamental economic changes that gave rise to modern Romania.He pointed out how, following the 1859 Union of the Principalities, massive Western investment had led to the emergence of a bourgeois middle class composed of "boyars" who had turned to trade, and of a capitalist economy.Moreover, he argued that continued industrialization and adoption of European technology, guided by this class, were necessary for Romania to avoid retrenchment.