Shamans were usually females and they were thought to be able to communicate with spirits and have knowledge above the normal man. Now before Joseon dynasty shamans had great trust from the royal family and citizens but during the Joseon dynasty they were considered outcasts. Shamanistic beliefs were still deeply rooted in common people and in Korea shamanism is still practiced and it has influenced e.g. Christianity in Korea.
Now I’m not completely sure if the drama is trying to pass Ae Sin as Heo Nanseolheon but as it doesn’t fit the time frame of the drama I’m going to assume that she was reading her poems. (*edit: she was reading her works)
So, Heo Nanseolheon is one of the few Joseon women remembered by her name know. She came from a yangban family and was thus educated. She was a poet and a couple hundred of her poems still remain. Interestingly her brother was a writer too and is credited as the writer of the first Korean novel: Hong Gildong.
Other History Bits for Mr. Sunshine: