Since the 7th millennium BC, the Stuttgart area has been an important agricultural area and has been host to a number of cultures seeking to utilize the rich soil of the Neckar valley. The Roman Empire conquered the area in 83 AD and built a massive near Bad Cannstatt, making it the most important regional centre for several centuries. Stuttgart's roots were truly laid in the 10th century with its founding by Liudolf, Duke of Swabia, as a stud farm for his warhorses. Initially overshadowed by nearby Bad Cannstatt, the town grew steadily and was granted a charter in 1320. The fortunes of Stuttgart turned with those of the House of Württemberg, and they made it the capital of their county, duchy, and kingdom from the 15th century to 1918. Stuttgart prospered despite setbacks in the Thirty Years' War and devastating air raids by the Allies on the city and its automobile production during World War II. However, by 1952, the city had bounced back and it became the major economic, industrial, tourism and publishing centre it is today.