《明史·列传·卷六十一》
孙镗草拟奏书，叩响东长安门，从门缝将奉书投人内廷，才得以招集军队捆住曹吉祥，防守皇城诸门。
镗草奏，叩东长安门，自门隙投入内廷，始得集兵缚吉祥，守皇城诸门。
Sun Tang swiftly drafted a memorial, knocked on the East Chang'an Gate, and slipped the memorial to the inner palace through a crack in the gate, only then was he able to gather troops, tie up Cao Jixiang, and defend the various gates of the imperial city.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 镗草奏，叩东长安门，自门隙投入内廷，始得集兵缚吉祥，守皇城诸门。 [/INST] Sun Tang swiftly drafted a memorial, knocked on the East Chang'an Gate, and slipped the memorial to the inner palace through a crack in the gate, only then was he able to gather troops, tie up Cao Jixiang, and defend the various gates of the imperial city.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 镗草奏，叩东长安门，自门隙投入内廷，始得集兵缚吉祥，守皇城诸门。
user
Sun Tang swiftly drafted a memorial, knocked on the East Chang'an Gate, and slipped the memorial to the inner palace through a crack in the gate, only then was he able to gather troops, tie up Cao Jixiang, and defend the various gates of the imperial city.
assistant