Hanover:

Hanover was founded in medieval times on the east bank of the River Leine. Its original name Honovere may mean "high (river)bank", though this is debated (cf. das Hohe Ufer). Hanover was a small village of ferrymen and fishermen that became a comparatively large town in the 13th century due to its position at a natural crossroads. As overland travel was relatively difficult, its position on the upper navigable reaches of the river helped it to grow by increasing trade. It was connected to the Hanseatic League city of Bremen by the Leine, and was situated near the southern edge of the wide North German Plain and north-west of the Harz mountains, so that east-west traffic such as mule trains passed through it. Hanover was thus a gateway to the Rhine, Ruhr and Saar river valleys, their industrial areas which grew up to the southwest and the plains regions to the east and north, for overland traffic skirting the Harz between the Low Countries and Saxony or Thuringia.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". When did Hanover become a comparitvely large town?
13th century