In the late 1st century BC and early 1st century AD, the Roman emperor Augustus launched campaigns across the Rhine, and sought to incorporate areas of Germania as far east as the Elbe into the Roman Empire. He planned to turn this area into the proposed province of Magna Germania, with headquarters at Colonia (modern-day Cologne, Germany). The Roman campaign was severely hampered by the victory of Arminius at the Battle of the Teutoburg Forest in 9 AD. The outcome of this battle dissuaded the Romans from their ambition of conquering Germania, and is thus considered one of the most important events in European history. The Rhine eventually became the border between the Roman Empire and Magna Germania. Areas of northeast Gaul bordering the Rhine remained under Roman control, and are often referred to as "Roman Germania". Four Roman legions were stationed there, and a Roman fleet, the Classis Germanica, was also established. The area was effectively governed as Roman provinces.