本文以统治地盘之取得以及扩张为内容线索，分为三个阶段探讨了东晋建国历程问题，旨在突破既有成说和补强薄弱环节，以期能够深化两晋之际政治史的研究。东晋建国创业，始于琅邪王司马睿、王导受主公东海王司马越之命渡江暨取得江东之地。以往只道是琅邪渡江是在永嘉元年（307）。事实上，早在两年前王、马就已获渡江之命，只因江东士族拥戴陈敏而不得渡，无奈寄寓在徐州下邳。当永嘉元年陈敏之乱平定，司马越一面召江东群英北上为官，实乃计划扣为人质，一面才再命王、马渡江。然而王、马此时已有异志，于是刻意结交这批江东名士，并违背主公意志暗中帮助他们逃归了江东，可信这才是王、马渡江后得以迅速打开局面的重要原因。而从渡江伊始至此后相当长时期，在面对司马越的人力物力大征发时，江东王、马在执行上虚与委蛇，更注重对本地利益的维护，则进一步稳固了江东基本盘。到了永嘉五年（311）初，江东王、马一举跨有江西之地，迈出了东晋建国的关键一步。这里通过两个以点带面的个案研究，对此役于东晋建国的意义稍作发掘。其一，通过揭示司马睿召庐江太守胡孟康渡江的复杂背景，表明出兵江西虽是有司马越之命，但王、马已经公然跟主公争夺地盘，可以说此役是王、马在政治上摆脱附庸、不再蛰伏的转折点。其二，通过考出桓彝家族出自社会身份不高的吴人将家，及吴亡后包括桓氏在内大量孙吴将吏被内徙江西，以证司马睿此时之任命桓彝为逡猷县令实乃拉拢本地豪杰，并由此推论当地如桓彝者势必也在拉拢之列，则内徙江西的善战斗之吴人群体就此转入江东王、马之手，而在相当程度上自吴亡以来被分割的吴人力量又再度合一。随着永嘉五年（311）六月洛阳的倾覆，此时霸主司马越已死以及晋怀帝被俘，西晋中央帝国实际上已经灭亡，也就是在这个时候江东当局再度出兵，由此正式开启了连绵近十年的王朝统一战争。这个阶段三面出击，其中溯江而上、力争上游是主攻方向，与此同时亦在经略南土与北伐中原。本文着重考述了轻取江州、入荆受阻、转进湘州和三取荆州这一系列政治过程问题，以及经略南、北之相关情况。其中，随着太兴二年（319）平定荆州，完成了一统上游，昔日孙吴之版图完全恢复，而东晋的建国至此亦告一段落。
Taking the acquisition and expansion of ruling territory as clues,this paper discusses the problems of Eastern Jin dynasty ’s establishment in three stages.Meanwhile,it tries to deepen the research on the political history between the Western and Eastern Jin dynasties for breaking through the existing theory and strengthening the weak links.The establishment of the Eastern Jin dynasty starts from the moment that Sima Rui and Wang Dao were going to capture the Jiangdong area under the order ofSima Yue.The time was often considered in Yongjia first year (307).In fact,Wang and Ma had gotten the order two years ago.But they failed, because the Jiangdong clans supported Chen Min faction. Therefore,they had no choice but to livein Xiapi,Xuzhou.After the Chen Min rebellion was suppressed,Sima Yue appointed Jiangdong group as officials,but actually he planned to take them hostage.On the other hand, heordered Wang and Ma to captureagain.However,Wang and Ma had disagreements secretly.Hence,they deliberately made friends with these Jiangdong celebrities and helped them escape.In view of this,we can infer that this is the important reason why Wang and Ma were able to open the situation quickly.For a long period,faced with Sima Yue’s massive recruitment of manpower and material resource,Wang and Ma executed courteously but without sincerity.They inclined to maintain local interests for consolidating Jiangdong area.Yongjia five years(311),Wang and Ma captured Jiangxi area, which was a key step for the establishment of the Eastern Jin dynasty.Through two case studies,this paper will explore the significance of this battle during the establishment of the Eastern Jin dynasty.First, through revealing the complex background of Sima Rui’s summoning Lujiang chief Hu Mengkang,it shows that although Sima Yue had ordered the troops to Jiangxi,Wang and Ma had openly fought for the territory with their leader.It can be said that this battle was a turning point for Wang and Ma to get rid of their vices and no longer stay in the limbo in politics.Second,through researching Huanyi family’s social status which is not noble,and a large number of Wu families and its subordinate will be migrated to Jiangxi area,this paper will demonstrate that Sima Rui’s real purpose is to draw local celebrities by appointing Huanyi as Qunyou chief.So from this,it can be concluded that local people such as Huanyi must also be drawn.The result is that militant Wu people were transferred into Wang and Ma’s domination. In a way,Wu people were united again.With the collapse of Luoyang in June,Yongjia five year(311),also Sima Yue had been dead and emperor Huaidi was captured, the central empire of the Western Jin dynasty had actually perished.At this time, the Jiangdong authorities sent troops again, which officially opened the unification war for nearly a decade.The war was divided into three sides: striving up along the Yangtze river which was the main attack direction, conquering the southern and northern region.This paper focuses on a series of political process problems,including conquering Jiangzhou,being hindered in entering Jingzhou,turning to Xiangzhou and conquering Jingzhou three times,as well as the relevant situation of conquering the south and north.After Jingzhou was pacified in Taixing two years(319),the unification of the upper reaches was completed.Finally, the territory of the former Sun Wu was completely restored,and the founding of the Eastern Jin dynasty came to an end.
