Editing Spring and Autumn period (section)

===Hegemony of Qi (685–643)===
{{Main|Duke Huan of Qi}}
<section begin="齊桓公霸" />The first hegemon was [[Duke Huan of Qi]] (r. 685–643).  With the help of his prime minister, [[Guan Zhong]], Duke Huan reformed Qi to centralize its power structure.  The state consisted of 15 "[[Administration of territory in dynastic China#County|townships]]" ({{zh|c=縣|labels=no}}) with the duke and two senior ministers each in charge of five; military functions were also united with civil ones.  These and related reforms provided the state, already powerful from control of trade crossroads, with a greater ability to mobilize resources than the more loosely organized states.{{Sfn |Hsu|1999 | pp = 553–54}}

By 667, Qi had clearly shown its economic and military predominance, and Duke Huan assembled the leaders of [[Lu (state)|Lu]], [[Song (state)|Song]], [[Chen (state)|Chen]], and [[Zheng (state)|Zheng]], who elected him as their leader.  Soon after, [[King Hui of Zhou]] conferred the title of ''bà'' (hegemon), giving Duke Huan royal authority in military ventures.{{Sfn |Hsu|1999|p=555}}{{Sfn |Lewis|2000|pp= 366, 369}}<section end="齊桓公霸" /> An important basis for justifying Qi's dominance over the other states was presented in the slogan 'Revere the King, Expel the Barbarians' ({{zh|labels=no|c=尊王攘夷|p=zun wang rang yi}}). The role of subsequent hegemons would also be framed in this way: as the primary defender and supporter of nominal Zhou authority and the existing order. Using this authority, during the first eleven years of his hegemony, Duke Huan intervened in a power struggle in Lu; protected [[Yan (state)|Yan]] from encroaching [[Xirong (people)|Western Rong]] nomads; drove off [[Beidi|Northern Di]] nomads after their invasions of [[Wey (state)|Wey]] and [[Xing (state)|Xing]], providing the people with provisions and protective garrison units; and led an alliance of eight states to conquer [[Cai (state)|Cai]] and thereby block the northward expansion of [[Chu (state)|Chu]].{{Sfn |Hsu|1999| pp = 555–56}}

At his death in 643, five of Duke Huan's sons [[War of Qi's succession|contended for the throne]], badly weakening the state so that it was no longer regarded as the hegemon. For nearly ten years, no ruler held the title.{{Sfn |Hsu|1999|p= 560}}

[[Image:China 2b.jpg|thumb|left|Urbanization during the Spring and Autumn period.]]