[炎黃子孫]: means Descendants of the Yan and Huang Emperors.
According to Chinese history, Yandi (炎帝) and Huangdi (黃帝) are the ancestors of the Huaxia people. Legend has it that they are all part of the Yanhuang tribe.
In the Battle of Banquan, Huangdi defeated Yandi eventually, and the two peoples gradually assimilated the other's culture, known as the Huaxia.
A few centuries later, Huaxia developed into a Han nationality, which is the majority of Chinese today. Huangdi is known as the founder of Chinese civilization.
Therefore, Chinese people always calls themselves as 'Descendants of the Yan and Huang Emperors'.