In summer 1916, Romania disappointed Arbore by rallying with the Entente. After a short-lived offensive into Transylvania, the Romanian Land Forces were defeated, and the Central Powers invaded southern Romania. Arbore stayed behind in German-occupied Bucharest while the legitimate government withdrew to Iași, and maintained a generally friendly but discreet attitude toward the occupiers. He was less active as a journalist and militant, but contributed to the Germanophile daily "Lumina", put out by the Bessarabian activist Constantin Stere, and once lectured on the Bessarabian question during April 1918. Arbore also kept a low profile during the 1918 truce, when, with German acquiescence, Romania united with Bessarabia. Reputedly, Stere, who negotiated the union with the Bessarabian Assembly, mistrusted and sidelined Arbore during the events.