he met Józef Piłsudski in December 1913. 1914–42 In 1914, he moved to Kraków and joined the First Cadre Company, which fought on the Austro-Hungarian side against Russia. In October 1914 he became a commander of a platoon of a squadron in . During the fighting in 1914–1915, he was promoted to lieutenant, and after the war he was awarded the V-Class Virtuti Militari. In August 1915, he moved to the special group in Warsaw. Soon he became an aide-de-camp to Józef Piłsudski. In 1918, he was sent on a mission to Russia. He was given three tasks: persuade General Józef Haller's army, then in the Ukraine, to back Piłsudski (he failed in this task); reach the French military mission in Moscow under General Lavergne (he succeeded in this task); and return from Moscow to Paris to liaise with the government there. Unfortunately, he was arrested by the Soviet Cheka as a member of the Polish Military Organisation while on a French diplomatic train on its way from Moscow to Murmansk (and Paris). He was imprisoned in the Taganka prison. He was freed thanks to the intervention of his future wife, Bronisława Wieniawa-Długoszowska, with the much-feared Cheka operative Yakovleva, then in charge of the prison. Bronisława, née Kliatchkin, was at that time married to the lawyer , the lawyer of Felix Dzerzhinsky, the head of the Cheka. She was a Lutheran, her family having converted from the Jewish faith when she was eight. He married her in a Lutheran ceremony on 2 October 1919 at Lutheran zbór in Nowy Gawłów. The marriage register records the details from her false French passport, including "Lalande" as her maiden name. As aide-de-camp of Józef Piłsudski during the Polish-Soviet War he helped him organize the Vilna Operation and Battle of Warsaw. He was also a commander of 1st Cavalry Division. After the war, Wieniawa was awarded many medals (including the Légion d'honneur, Cross of Valor and Cross of Independence). Throughout the interwar years, he was a key figure in Warsaw literary and social life. He had a table reserved for him with leading Warsaw literary figures, such as Julian Tuwim and Jan Lechoń, at the mezzanine of the café . In a famous anecdote, Aleksander Wat recounts how, when Wat was imprisoned, by the government of the Second Polish Republic for his literary activities (he was the publisher of the crypto-communist magazine ), he