歷來關於長安╱西安的城市研究獨好唐以前的「長安都城史」，至今仍無堪稱「西安城市史」的論著問世。城市史的書寫深刻影響城市保存的實踐：西安市政府近年來積極推動的「唐皇城復興計劃」同樣漠視唐以後西安的變遷。唐大明宮遺址公園的建設是「復興計劃」的重要組成，極具代表性與示範意義：意圖藉由物質形式的「保存」與「恢復」，在三年內迅速讓「70 年來髒、亂、差的道北棚戶區和城中村」歸返「1400 年前的盛唐皇宮」。期間省略的千餘年歷史真如此無足輕重？抑或刻意略而不提？本文着重分析此種歷史敘事及歷史保存「不連續」現象的起因，耙梳被遺漏的歷史片段有何重要性。相對於將近世西安視為「沉睡、遲滯」的論述，本文試從「流動」的角度切入，並聚焦於大明宮（遺址）的地景變遷。本文發現觀察出、入於大明宮（遺址）之人與物的動向、流動速度與規模，可見微知着地窺見長安╱西安城市整體興衰以及在國家戰略佈局中定位的變異。基於對大明宮（遺址）千餘年歷史的考察，本文發現當局利用大明宮遺址公園地景重新謄寫的是一部以漢族為中心、圍繞帝王將相盛世風華的歷史。在大明宮遺址的「保護」實踐過程中，蒙、回、河南人、建材城和城中村……的歷史反而佚失了。

The historiography about Chang’an (in present-day Xi’an, Shaanxi) has been mainly about the city’s imperial past of the Tang dynasty or earlier stages (before the end of the 9th century AD). Not being the capital anymore, Chang’an after the Tang dynasty was out of the literati’s and scholars’ attention. In the writing of Xi’an’s urban history, time seems to halt as we see recalling or imagining the remote past while disregarding immediate transformation. The way history has been compiled and narrated significantly influences the practice of heritage conservation today. In the year of 2005, the municipality of Xi’an initiated the “Tang royal city renaissance scheme” aiming at revitalizing the stigmatized “stagnant and sleepy” city of Xi’an by remodeling it after the flourishing yet distant empire. More than a span of one millennium in-between was intentionally skipped. The remodeling of Daming Palace, one of grand Tang’s political cores, is an obvious example of this revitalization movement. Within three years, the former palace has been transformed into a gigantic Tang-themed urban heritage park from sites of slums, urban villages, factories, and dumping grounds. With the execution of the heritage site conservation and heritage park construction, ironically, the history of the Mongolians, the Muslins, refugees from He’nan province and other disadvantaged minorities was carefully wiped out. The official wording of “conservation” in this case implies the action of selecting favorable memories. This article analyzes the reasons why certain ethnic groups and specific periods of history were deliberately excluded, and demonstrates the necessity to reveal the undesirable past. Instead of regarding Xi’an as being inactive and still, this article emphasizes the perspective of motion and dynamics for better elaborating on the long-term spatial transformation. From observing the direction, velocity and capacity of people and materials moving in and out of the site, this article finds that Daming palace represents the epitome of the changing strategic position of Xi’an city within the whole country.