Why called Tianjin?

After the death of Zhu Yuangzhang, the first emperor of the Ming Dynasty, Zhu Li, his fourth eldest son, rebelled against the government led by Zhu Yunwen, the eldest grandson of Zhu Yuanzhang. At that time, the capital of the Ming Dynasty was Nanjing in the south China, and Zhu Li was the Yan King, guarding the north. Zhu Li¡¯s troops started from Beijing, crossed a river smoothly at Zhigu (the old name of Tianjin), and captured the Cangzhou Town to the south in 1400. Finally he attacked and occupied the Nanjing City, and crowned himself as the Emperor in 1403. Zhu Li selected Beijing as his capital, and began to build the Forbidden City. In 1404, he named the Zhigu as Tianjin. Tian means the Son of Heaven, and Jin means the River Ferry, that¡¯s to say, Tianjin is the Ferry of the Emperor.