(island)
The island of Saint-Géry—or Grand Île—was the largest of three islands in the Senne River. It was located on the current site of the place Saint-Géry. Legend holds that Saint Géry built a chapel on the island circa 695, and it is a traditional locale of the ducal castrum. It was linked to the surrounding environs by three bridges—the Spiegelberg (at the current boulevard Jules Anspach and rues de Borguel and des Pierres), the Haut Font (later called the Pont des Juifs), and the Hollant bridge. Tradition has always held that the Île Saint-Géry constitutes the original center of Brussels.
Historical Dictionary of Brussels. Paul F. State.