the izaak synagogue or isaac synagogue, formally known as the isaak jakubowicz synagogue, is a prayerhouse built in 1644 in the historic kazimierz district of kraków, poland. the synagogue is named for its donor, izaak jakubowicz (d. 1673), also called isaac the rich, a banker to king władysław iv. the synagogue was designed by francesco olivierri, an italian working in poland in that era. jakubowicz is buried in the remah cemetery. variants of the name include ayzik, izaak, and isaac. izaak is the standard polish spelling, while jakubowicz is polish for a "son of jacob."