Tianjin was called Haijin Town, Zhigu Zhai and Tianjin Wei in ancient times.

Tianjin's present location is an alluvial plain formed by sediment alluviation before the Yellow River was diverted in ancient times. The ancient Yellow River was diverted three times to enter the sea near Tianjin, 3,000 years ago in the vicinity of Ninghe County, in the Western Han Dynasty in the vicinity of Huanghua, and in the Northern Song Dynasty in the southern outskirts of Tianjin. During the Jin Dynasty, the Yellow River was diverted to the south and the coastline of Tianjin was fixed. By the time of the Warring States period at the latest, there was already an ancestral people working and living here.

During the Western Han Dynasty, Emperor Wu of Han set up a salt official in Wuqing. With the opening of the Grand Canal in the Sui Dynasty, the "Three Forks of the River", where the South Canal and the North Canal meet, became the earliest birthplace of Tianjin.

During the Tang Dynasty, salt fields were opened in Lutai and salt warehouses were set up in Baodi. After the middle of the Tang Dynasty, Tianjin became a land and water port for the northward transportation of grain and silk from the south. The Haihe River was once the boundary river between Song and Liao, and was divided between Song and Liao in the north and south.

The Song Dynasty set up many military strongholds south of the Hai River, such as Nanhe, Shahe, Duliu, etc., to prevent the Liao army from moving south. The Jin Dynasty set up a military stronghold, Zhigu Zhai, at Sanqikou, where a street was formed near Tianhougong (Heavenly Queen's Palace) at that time.

During the Yuan Dynasty, when the sea and waterways were opened, Zhigu became a hub of waterways and transportation, and for this reason, Zhigu set up the Receiving Office and Linqing Wandu House, and built granaries and Tianhou Palace. 1316, the town of Haijin was set up in Zhigu, and it was a military town and transportation center at that time.

Expanded Information:

Tianjin, which came from the ancient times, was once a land of receding sea. The Yellow River, which has the highest sand content in the world, entered the sea through Tianjin three times in history and silted up into the Tianjin Plain with amazing land-making ability.

To this day, some shell dykes remain in Tianjin's Shanggulin and other places, which archaeologists say are remnants of the ancient coastline. The forefathers of Tianjin lived and prospered on this piece of land, experiencing countless historical openings and closings and changing times.

Tianjin's name began in China's Ming Dynasty. After Zhu Yuanzhang, the founding emperor of the Ming Dynasty, ascended the throne, he divided his sons into kings and stationed them all over the country.

His fourth son, Zhu Di, was named King of Yan and stationed in Beiping, now Beijing. When Zhu Yuanzhang died, he passed the throne to his eldest grandson, Zhu Yun炆(朱允炆). Zhu Di launched the Battle of Jingnan in Chinese history in order to compete with Zhu Yunbao for the throne.

Reference:Baidu Encyclopedia-Tianjin