Complex sentence: In 2009 Viktor Mitic joined the Odon Wagner Gallery & Contemporary, who exhibited his famed "Blasted Guernica" at the international exhibition Art Toronto (formerly the TIAF) the previous October.
Split into simpler sentences: In 2009 Viktor Mitic partnered with the Odon Wagner Gallery & Contemporary. The Wagner Gallery had exhibited his famed "Blasted Guernica" at the international exhibition Art Toronto (formerly the TIAF) the previous October.