The Convention of Artlenburg or Elbkonvention was the surrender of the Electorate of Hanover to Napoleon's army, signed at Artlenburg on 5 July 1803 by Oberbefehlshaber Johann Ludwig von Wallmoden-Gimborn. It disbanded the Electorate of Hanover and instigated its occupation by French troops.
Context
After Napoleonic troops under lieutenant-general Édouard Adolphe Casimir Joseph Mortier occupied the electorate's capital at Hanover on 4 June 1803, the remaining Hanoverian troops withdrew to the north bank of the Elbe, into the Duchy of Saxe-Lauenburg, but were soon forced to surrender.
References
Convention of Artlenburg Wikipedia(Text) CC BY-SA