Bak Yeon or Park Yeon (Korean: 박연; 20 August 1378 – 23 March 1458[1]) was a government official, scholar, writer, astronomer and musician in the Early Joseon Dynasty period, who was a teacher of King Sejong and created Armillary sphere Honcheonui, Water clock Borugak Jagyeongnu and sundial Yangbu Ilgu along with Jang Yeong-sil and five basic sounds(Gung, Sang, Gak, Chi, Wu), which corresponds to five consonant groups (Aeum, Seoreum, Suneum, Chieum, Hueum) in Hunminjeongeum.

He then has successively filled various government posts including Jiphyeonjeon, Saganwon, Saheonbu and Sejasigangwon Munhak, where he met Chungnyeong daegun.

As soon as Sejong ascends the throne in 1418, he appoints Bak Yeon to an agency affiliated with Yejo, which oversees music-related affairs.

[12][13] On 22 August 1443, when Pak Yeon was 60 years old, his position was suddenly changed from Yejo chamui(禮曹參議) to Jungchuwon busa(中樞院副使), which oversees the palace in shifts.

His descendants were prohibited from taking gwageo exams for 331 years until king Yeongjo awarded him an honorable title of Mun Heon in 1767.