while langdon would never consider st. mark 's a stand-in for the spectacular mosques of turkey , he did have to admit that one 's passion for byzantine art could be satisfied with a visit to the secret suite of rooms just off the right transept in this church , in which was hidden the so-called treasure of st. mark-a glittering collection of 283 precious icons , jewels , and chalices acquired during the looting of constantinople .