You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Zhejiang

Context:
During the First Opium War, the British navy defeated Eight Banners forces at Ningbo and Dinghai. Under the terms of the Treaty of Nanking, signed in 1843, Ningbo became one of the five Chinese treaty ports opened to virtually unrestricted foreign trade. Much of Zhejiang came under the control of the Taiping Heavenly Kingdom during the Taiping Rebellion, which resulted in a considerable loss of life in the province. In 1876, Wenzhou became Zhejiang's second treaty port.

Question:
During which war did the British navy defeat Eight Banners forces at Ningbo and Dinghai?

the First Opium War