The land where Tianjin is located today was created in between 900 and 1300 CE by sedimentation of various rivers entering the sea at Bohai Gulf, including the Yellow River, which entered the open sea in this area at one point. The construction of the Grand Canal under the Sui dynasty helped the future development of Tianjin as the canal ran from Hangzhou to the Beijing and Tianjin region by 609 CE. Grain from southern China was regularly transported to the north through the canal and was used during the subsequent dynasties.