In other words, Xixia was not without historical records, but was deliberately "belittled" by people in the Yuan Dynasty for political needs. Not only the Biography of Xia Guo in the Song Dynasty recorded Xixia in detail, but also the Mongolian historical materials in the Yuan Dynasty recorded Xixia in detail, and this so-called Xixia is Xixia! Therefore, since Emperor Li of Xixia, emperors of all dynasties have detailed lineages and recorded historical events completely. There is no "discovery of Xixia" as the questioner said. Xixia has always existed. Xixia has never been submerged by history since its existence.
The questioner must have confused the Xixia characters discovered by Zhang Shu in Qing Dynasty with the Xixia history. In fact, Zhang Shu was not the first to discover Xixia characters, but he studied them specially and published "papers". There is a book, books, stone carvings, etc. Has always existed in Xixia. Just because of the demise and age of Xixia, Xixia became a "extinct language", and no one can interpret it. Over time, Xixia characters were forgotten by people. However, cutie's discovery revived people's interest in Xixia characters and started a new round of Xixia characters research.
However, the research is not smooth, and it is difficult to explain all Xixia characters completely different from Chinese characters. It was not until a "tomb-robbing archaeology" in Russia that all this changed. At the end of the Qing Dynasty, Russian kozlov discovered the site of Xixia Black Water City in the desert and found a large number of Xixia documents. After that, kozlov shipped all these things back to Russia. Among these stolen cultural relics, there is a book "Mother of Pearl in Fan Han's Hand", which is a comparative dictionary of Chinese and Xixia languages in Xixia period. With this key, people's interpretation of Xixia characters has also embarked on the fast track, and a large number of Xixia "death languages" have been "resurrected". Many Xixia history submerged in the long river of time has also been rediscovered.
The questioner obviously has a little knowledge, which confuses Xixia history and Xixia characters. Xixia didn't disappear, the Yuan Dynasty destroyed Xia Hou, and the Tangut people didn't really disappear, but merged into various ethnic groups. The written records about Xixia have always existed and are quite complete. Even the Xixia script has not disappeared, but it has become a "language of death" because of its long history and is gradually forgotten by people.