Pont Sully: There used to be two footbridges upstream from the île Saint-Louis: one was the Damiette, on the right bank, the other was the Constantine, on the left bank. The latter was a suspension bridge that was built in1836 and collapsed twenty years later.A pedestrian crossing raised on piles joined the upstream tip of the island to the Quai Henri IV (Henri IV Quay) whose role was to protect from ice the boats moored in winter in the Port des Célestins (Célestins Port), Saint Paul, on the small branch of the Seine. It did not disappear from the Parisian landscape until 1933. The structure that replaced it is in honour of Maximilien de Béthune, Duke of Sully, a Minister of Henri IV, hence its name. The special feature of this structure is that it is made of two standalone metal bridges that stand on the tip of the île Saint-Louis; it was the work of the engineers Vaudrey and Brosselin during the Second Empire. These bridges link Boulevard Henri IV and Boulevard Saint Germain. The North Bridge starts at Quai Henri IV and ends at Quai d'Anjou, while the South Bridge starts at Quai de Béthune and comes out on the Saint Bernard and La Tournelle quays.