What is the background of the title of Lin 'an Mansion?

Two poems, Lin 'an Mansion and Feeling of Leaving the Fence Gate in Autumn Night, are based on the history that the Northern Song Dynasty was captured by the nomads, the Central Plains was occupied, the two emperors (Hui Zong) and (Qin Zong) were captured, and the Southern Song Dynasty emperor established his capital in Lin 'an. The author of the first song describes what he saw and heard in Hangzhou, satirizing and exposing (the dignitaries in the Southern Song Dynasty were all having fun, living in a drunken dream), and the last two sentences reflected the poet's concern for the country and the people.

[Creation Background] Sixty-eight-year-old Weng Fang has been to his hometown in Yin Shan for four years. But the quiet country life can't calm the old man's heart. Although it is early autumn, the summer heat is still strong, and the hot weather and inner boiling make him unable to sleep. At dawn, he stepped out of the hedge door to cool off and wrote two poems.