Joachim the Korsunian (Russian: Иоаким Корсунянин - Ioakim Korsunianin) was the first bishop of Novgorod the Great (r. ca. 989-1030). As his surname suggests, he probably came from the Byzantine town of Cherson (Korsun) on the Crimean Peninsula and was sent to Kievan Rus' about 989 (sources differ on the precise year of his arrival in Kiev or later in Novgorod). Upon his arrival in Novgorod, he cast the idol of the god Perun into the Volkhov River and built the Perunskii Monastery on the site where it once stood. He also built the first, wooden, Cathedral of the Holy Wisdom on the site of a pagan cemetery (although this was not discovered until archaeological excavations in the 20th century). He also built the Church of Joachim and Anne, named for his patron saints, which stood near the present site of the Cathedral of Holy Wisdom. He was buried there on his death in 1030, but his remains were transferred into the current cathedral in 1598.
Very little is known of his episcopate; although the Ioakimovskaia Letopis (Ioachim Chronicle) is traditionally attributed to him, this is now considered to be highly questionable. It is more likely a seventeenth-century compilation and is now often attributed to Patriarch Ioakim of Moscow (d. 1690) rather than Ioakim Korsunianin. Upon his death in 1030, his disciple, Efrem, administered the eparchy for five years (1030–1035) until the arrival of Luka Zhidiata.
Ioakim is venerated as a saint by the Russian Orthodox Church. His feast days are February 10 (the feast of the Novgorodian Saints, in which 10 other bishops and archbishops and others are commemorated) and June 19.