崇禎十七年（1644），李自成（1606-1645）攻入北京，崇禎皇帝（1611-1644）自縊，結束明帝國的統治。然明帝國在江南仍保有半壁江山，留都南京更有中央機構，只需新立皇帝，南京的明代政府又能持續運作。崇禎帝駕崩之消息傳到南京後，南京諸臣開始尋找新皇帝的人選，其倫序來看有神宗嫡孫福王朱由崧（1607-1646）；以賢明作為考量，則有神宗之侄潞王常淓（1608-1646）。所以南京諸臣對於立福或是立潞出現分歧。以馬士英（?-1646）為主的地方官員與武將認為福王倫序當立，但是以史可法（1601-1645）為主的東林官紳一派認為較為賢明的潞王是最好人選。最後士英與地方武將藉著兵力優勢，以倫序當立為由，擁立福王登基，士英也因此進入內閣辦事。士英入閣後，諸臣認為長江防線需要有大員督師，方能確保南京安全。朝中大臣皆認為士英是督師最佳人選，然江北武將與揚州士紳希望由可法擔任，基於前線考量，最後由可法出任督師。可法至揚州擔任督師，而士英正位為首輔，形成弘光朝政上的一個態勢。

The Seventeenth year of Chongzhen （1644）, Li Tzu-cheng （李自成, 1606-1645） and his army force entrance into the Beijing, and the Emperor Chongzhen hang himself and it came the end of Ming Dynasty. But Ming dynasty still hole half of the country, and the central government also existed in the second Capital—Nanjing. What they needed was to support a new Emperor, and then the Ming Government of Nanjing can keep working. After the news of the death of Emperor Chongzhen transmits to Nanjing, all government officials started to looking for a new Emperor. By succession, it seems to be Prince of Fu—Chu You-song （朱由崧, 1607-1646）, who was the grandson of Emperor Wanli; by the consider of moral concept, it should be Prince of Lu—Chu Chang-fang （朱常淓, 1608-1646）, who was the nephew of Emperor Wanli. The government officials had different ideas of supporting the new Emperor. The group led by Ma Shih-ying （馬士英, ?-1646）, which consisted by local officials and generals, support Prince of Fu as new Emperor, but the opposite group, composed by Tunglin movement and headed by Shih Ko-fa （史可法, 1601-1645） thought Prince of Lu, who has better wise, must be the Emperor. At the end, Ma Shih-ying and local generals take the advantage of armies, used order of succession as the reason, let the Prince of Fu became the Emperor successfully. Therefore, Ma Shih-ying became the cabinet minister. After he turned into the cabinet minister, government officials wished to ensure the safety of Nanjing suggested that the defense line of Yangtze River must have a Marshal. All the government officials thought Ma Shih-ying was the best one to be the Marshal, but local generals and bourgeois of Yangzhou wished Shih Ko-fa could be the person been selected. Based on consideration of front line, Shih Ko-fa became the Marshal. Shih Ko-fa went to Yangzhou as the Marshal, and Ma Shih-ying was the cabinet minister, this was the circumstances of Hongguang Government.