In 1800, he received command of the army in the Helvetic Republic, maintaining communications between the armies of Germany and of Italy. He carried out his orders diligently, and in the winter of 1800-01, he was ordered to march over the Splügen Pass at the head of the Army of the Grisons. This achievement is described by Mathieu Dumas, his chief of staff. It is sometimes considered as noteworthy as Bonaparte's passage of the St Bernard before the Battle of Marengo, although MacDonald did not fight a battle.