"Dong Yi" is a historical drama based on the life of Dong Yi later known as Choi Suk Bin. She worked in the royal palace as a lowly water maid. King Sok Jong then selected Choi as his concubine. Choi would then give birth to Yeong Jo, the second son of King Sok Jong and the future king of Joseon. After the birth of Yeong Jo, Dong Yi would become Suk Bin. (Source: AsianWiki)