The style developed in Venice in the late 16th century, mainly through the work of Andrea and Giovanni Gabrieli, who were working in the unique acoustical space of St. Mark's Basilica. Different choirs or instrumental groupings occupied positions across the basilica from each other: because of the sound delay from one side to the other in the large and acoustically "live" space, a perfect unison was difficult, and composers found that a fantastically effective music could be composed with the choirs singing across to each other, in stereo as it were; all accompanied by organ or other groups of instruments placed in such a way that they could hear each group equally well. Music written there was quickly performed elsewhere, and compositions in the new "concertato" style quickly became popular elsewhere in Europe (first in northern Italy, then in Germany and the rest of Italy, and then gradually in other parts of the continent). Another term sometimes used for this antiphonal use of the choirs in St. Mark's was cori spezzati. See also Venetian polychoral style and Venetian School.