Jongmyo Jeryeak is government-designated Important Invisible Cultural Property No. l. Botaepyeong's 11 pieces and Jeongdaeeop's 11 pieces were first composed by King Sejong in 1446 to pray for national security and prosperity. The music was revised a bit and completed by King Sejo. Particularly, Botaepyeong-ak and Jeongdaepyeong-ak are praised to be almost perfect as music works in the composition of scores, fullly utilizing the inherent merits of traditional Korean scales.
Whereas the Baroque ritual music in Europe was born in the 17th century, Jongmyo Jeryeak came to being some 200 years before that. Jongmyo Jeryeak largely comprises voluminous concussion instruments and delicate string instruments, and the beautiful combination of their tone colors produce a solemn and mafnificent music befitting the most important national rite of Jongmyo Jerye. Jeryeak is classified into two categories of Deungga and Heonga by the location of performance and composition of instruments. Deungga is the orchestra which is positioned on the upper terrace of Jeongjeon to play music wthout songs, while Heonga plays music with songs on the lower terrace. Jeryeak is supposed to be in harmoney with Heaven and Earth.
Most of the instruments are made of natural material such as wood or stone, and the soft and warm tone colors and long, quiet reverberating sounds modify the often rigid ritual music into a mild one. The songs of Jeryeak, called Akjang, contain largely verses in praise of the many meritorious achievements of previous kings and their gallant military exploits.