▁musical ▁form ▁that ▁comb ines ▁singing ▁and ▁pro se ▁to ▁port ray ▁a ▁story . ▁Its ▁development ▁likely ▁origin ates ▁from ▁sh aman ▁rit uals ▁and ▁the ▁songs ▁within ▁the ▁Je ol la ▁Province .   It ▁became ▁a ▁full - f led ged ▁musical ▁form ▁by ▁the ▁middle ▁of ▁the ▁eigh teenth ▁century , ▁and ▁not ▁long ▁there after ▁the ▁y ang ban ▁arist ocracy ▁also ▁became ▁interested ▁in ▁it .   Origin ally ▁there ▁was ▁a ▁set ▁of ▁twelve ▁stories ▁that ▁were ▁s ung , ▁but ▁only ▁five ▁were ▁written ▁down , ▁and ▁hence ▁those ▁five ▁are ▁the ▁only ▁ones ▁s ung ▁today .   H aving ▁been ▁developed ▁by ▁common ers , ▁p ' ans ori ▁usually ▁reflected ▁their ▁att itudes ▁and ▁asp ir ations , ▁but ▁by ▁becoming ▁popular ▁with ▁the ▁y ang ban , ▁p ' ans ori ▁shift ed ▁somewhat ▁toward ▁y ang ban ▁sens ib ilities ▁and ▁restrictions .   P ' ans ori ▁had ▁a ▁strong ▁influence ▁of ▁the ▁writing ▁of ▁the ▁time , ▁both ▁because ▁of ▁the ▁p ' ans ori ▁novel ▁( each ▁based ▁on ▁one ▁of ▁the ▁twelve ▁stories ) ▁and ▁by ▁increasing ▁the ▁real ism ▁of ▁the ▁classical ▁novel . ▁ ▁Science ▁and ▁technology ▁▁ 1 5 th ▁century ▁ ▁The ▁Jose on ▁D ynast y ▁under ▁the ▁reign ▁of ▁Se j ong ▁the ▁Great ▁was ▁Korea ' s ▁greatest ▁period ▁of ▁scientific ▁adv ancement . ▁Under ▁Se j ong ' s ▁new ▁policy , ▁Che on min ▁( low -