War followed and in 1842, the Treaty of Nanking was signed by official representatives of both Britain and China. It allowed the opening of major five major Chinese ports, provided indemnification for the opium destroyed and completed the formal acquisition of the island of Hong Kong, which had been officially taken over as a trading and military base on 26 January 1841, though it had already been used for years as a transhipment point. Trade with China, especially in illegal opium, grew, and so did the firm of Jardine, Matheson and Co, by that time already known as the "Princely Hong" for its status as the largest British trading firm in East Asia.