3 December 1360, he declared Aalen an Imperial City, that is, a city or town responsible only to the emperor, a status that made it a quasi-sovereign city-state and that it kept until 1803. In 1377, Aalen joined the Alliance of Swabian Cities, and in 1385, the term civitas appears in the town's seal for the first time. In 1398, Aalen was granted the right to hold markets, and in 1401 Aalen obtained proper jurisdiction. The oldest artistic representation of Aalen was made in 1528. It was made as the basis of a lawsuit between the town and the Counts of Oettingen at the Reichskammergericht in Speyer. It shows Aalen surrounded by walls, towers, and double moats. The layout of the moats, which had an embankment built between them, is recognizable by the present streets named Nördlicher, Östlicher, Südlicher and Westlicher Stadtgraben (Northern, Eastern, Southern and Western Moat respectively). The wall was about tall, 1518 single paces () long and enclosed an area of . During its early years, the town had two town gates: The Upper or Ellwangen Gate in the east, and St. Martin's gate in the south; however due to frequent floods, St. Martin's gate was bricked up in the 14th century and replaced by the Lower or Gmünd Gate built in the west before 1400. Later, several minor side gates were added. The central street market took place on the Wettegasse (today called Marktplatz, "market square") and the Reichsstädter Straße. So the market district stretched from one gate to the other, however in Aalen it was not straight, but with a 90-degree curve between southern (St. Martin's) gate and eastern (Ellwangen) gate. Around 1500, the civic graveyard was relocated from the town church to St. John's Church, and in 1514, the Vierundzwanziger ("Group of 24") was the first assembly constituted by the citizens. Reformation Delegated by Württemberg's Duke Louis III, on 28 June 1575, nearly 30 years after Martin Luther's death, Jakob Andreae, professor and chancellor of the University of Tübingen, arrived in Aalen. The sermon he gave the following day convinced the mayor, the council, and the citizens to adopt the Reformation in the town. Andreae stayed in Aalen for four weeks to help with the change. This brought along enormous changes, as the council forbade the Roman Catholic priests to celebrate masses and give sermons. However, after victories of the imperial armies at the