历史上的西安是一直在不停地改名字吗？为什么？

{!PGC_VIDEO:{"thumb_height":360,"file_sign":"246d727135d1c05bb44573a0e6**d135","vname":"","vid":"v02016d10000bfkjt8kthbi68g9j01b0","thumb_width":640,"video_size":{"high":{"duration":294.789,"h":480,"subjective_score":0,"w":854,"file_size":**},"ultra":{"duration":294.789,"h":720,"subjective_score":0,"w":1280,"file_size":**},"normal":{"duration":294.789,"h":360,"subjective_score":0,"w":640,"file_size":**}},"src_thumb_uri":"1132d00027be2af348075","sp":"toutiao","update_thumb_type":1,"vposter":"http://p0.pstatp.com/origin/**f**f3","vu":"v02016d10000bfkjt8kthbi68g9j01b0","duration":294.789,"thumb_url":"**f**f3","thumb_uri":"**f**f3","md5":"246d727135d1c05bb44573a0e6**d135"}-}