Iorga was again abroad in 1926 and 1927, lecturing on various subjects at reunions in France, Italy, Switzerland, Denmark, Spain, Sweden and the Kingdom of Yugoslavia, many of his works being by then translated into French, English, German and Italian. His work for 1926 centered on the first of four volumes in his series "Essai de synthèse de l'histoire de l'humanité" ("Essay on the Synthesis of World History"), followed in 1927 by "Istoria industriei la români" ("The History of Industry among the Romanians"), "Originea și sensul democrației" ("The Origin and Sense of Democracy"), a study of Romanian contributions to the 1877–1878 Russo-Turkish War ("Războiul de independență", "The War of Independence") etc. At home, the PND's merge into the PNR, accepted by Iorga, was stopped once the historian asked to become the resulting union's chief. Acting PNR leader Iuliu Maniu successfully resisted this move, and the two parties split over the issue.