Most cultures have a concept of an afterlife, that there is something outside of this world that acts as a guiding force for the world of the living, and we should strive for the best of things in something other than our current living world. Ancient China is no exception to this. The Terracotta Warriors were built by the first emperor of unified China Qin Shi Huang during the Qin Dynasty.
The purpose of the warriors was to protect the emperor in the afterlife and serve as a reflection of his life in this world. He believed that by making these reflections of our world, that he would recieve their benefits in the afterlife. The massive scale of these thousands of warriors goes to prove how much he valued his own legacy.
Religion and legacy often go hand in hand no matter which faith it is. For the emperor, preserving his life with vast numbers of man-made soldiers was his way of giving himself something in the world beyond, while leaving a sign here that he was someone important. Though the tomb was hidden and parts of it still remain hidden, the idea of preserving a physical memory of one's life still remains. For other faiths, preserving one's legacy in preparation for the afterlife may involve specific preservation of the body. One may also use their faith to preserve their legacy by placing a higher value on ancestors and their legacy, thereby establishing the concept that remembering the people of the past is inherently important.