Upon mobilization in August 1914, the Royal Saxon Army became the German
Third Army and Hausen was given command. His army participated in the
Battle of the Frontiers, mainly in the battles of
Dinant, where Hausen's troops summarily executed over 600 of its inhabitants, including several women and children (one of them just 3 weeks old), and
Charleroi, and he and his army were responsible for the destruction of
Reims in September 1914. When asked about how such deeds would eventually be known into history, he replied:"We should write history ourselves."After the
Second Army's retreat after the
First Battle of the Marne, Hausen saw his own flank exposed and ordered a retreat. After the stabilization of the front on the
Aisne River, on September 9, 1914, Hausen was relieved of his command due to illness and replaced by General
Karl von Einem. Hausen held no further field commands during the war, and died shortly after the war ended. He was occupied by writing about his memories during his last years. ==Dates of rank==