In 612, King Theudebert II of Austrasia was defeated by King Theuderic II of Burgundy near Toul. By the Treaty of Meerssen of 870, Toul became part of East Francia, the later Holy Roman Empire. During the High Middle Ages, it became a Free Imperial City. Toul was annexed to France by King Henry II in 1552; this was recognized by the Holy Roman Empire in the Peace of Westphalia of 1648. It then was a part of the French province of the Three Bishoprics.
During the siege of 1870 during the Franco-Prussian War, the last time that Toul's defenses were used as a classical fortress, 64 guns opened fire at 6am on September 23, and the fortress surrendered at 3pm after 2,433 shells had been fired.
There is a great deal of Roman archæology in the area and allegedly some in the town. The Roman fortified town of Grand is some 30km away, with its great amphitheatre and temple to the Cult of Apollo.
The old town's architecture is dominated by past glories in various states of decay, including a major gothic cathedral, which is in a poor condition and is being slowly restored. Many of the houses were built as canonical residences in the Late Middle Ages and bear vestiges in the form of ornamental stonework.
There is no trace of the monastery, however its wine-cellars still exist, under the shops on the North side of the Rue Gambetta. (Access is possible via the Camera Shop).
Toul is at the intersection of the Moselle River (which divides into the river proper and the Moselle Canalisée just outside the town) with the Canal de la Marne Au Rhin, and was once, consequently, an important port. The barges known as péniches still navigate these watercourses commercially, typically carrying steel, though in the summer much more of the water traffic is for pleasure.
There is a main-line railway station at Toul, the last major station before the (once vast, and still very large) marshalling yards at Nancy. However, the Paris-Strasbourg TGV line, now under construction, will pass about 20km north of Toul, approximately mid-way between Metz and Nancy. Its completion will likely reduce Toul's importance as a station.