唐前期营州事件与河北三层防御体系构建

The Incident of Ying Zhou and Constructing of Three-tier Defense System in Hebei during Early Tang Dynasty

武则天万岁通天元年契丹之乱以来,唐朝先后尝试了组织行军、设置团结兵、增置军镇等多种方式,皆未能改变唐朝在东北防御方面的被动局面。营州陷落之后,并州一度成为幽州的后援,与朔州、幽州共同构成跨区域联合防御模式,其防御对象不仅包括契丹、奚,也包括突厥,这是防线被迫后移西撤的一种无奈应对。直到开元年间,借由突厥内部权力过渡之机,并通过和亲两蕃等手段,才实现了营州的复置。与此同时,河北五军相继设立。开元二十年左右,河北三层防御体系形成,东北边地便捷报频传。但幽州节度使统领河北二十四州府的全境防御模式也导致了地方军事化的加深,这成为天宝之乱的一大诱因,也是安史之乱后河北分裂割据的一大事实基础。

Since the rebellion of Khitan in the 1^(st) year of Wansuitongtian,many ways were been tried by Tang dynasty such as organizing marches,setting up united soldiers and adding military garrisons,but the passive situation was not changed.After the falling of Ying Zhou,Bing Zhou became the backing of You Zhou,which cooperated with Shuo Zhou and You Zhou to defend against Khitan,Hsi and Turks.The helpless arrangement was forced by the retreatment of defense line.Until the Kaiyuan era,the Turkic Khan was dead,Tang dynasty used the opportunity and intermarried with Khitan,so,Ying Zhou was repeated.Meanwhile,the Five Military Garrisons were established in Hebei.In the 20th year of Kaiyuan,the three-tier defense system was formed,Tang dynasty kept winning in north-east area.But,the mode of Youzhou military governor commanding 24 prefectures lead to the problem of local militarization.This was one of the reasons for the rebellion and separation in Hebei region.