Time for a summary:

0-100 - TRUE
100-200 - ???
200-300 - FALSE
300-400 - ???
400-500 - ???
500-600 - FALSE
600-700 - TRUE
700-800 - ???
800-900 - ???
900-1000 - ???
1000-1100 - TRUE
1100-1200 - ??? - some way with this.
1200-1300 - TRUE (but 6-part as Greg points out)
1300-1400 - ???
1400-1500 - ??? - some way with this
1500-1600 - FALSE
1600-1700 - FALSE
1700-1800 - TRUE
1800-1900 - ??? - Most of the way there, but ... TRUE or FALSE???
1900-2000 - ???

As an indication to how useful a clustered search like Vivisimo can be, have a look at this search on "morality play" plainchant. Cracked it yet?

BTW ... Wot abaht the bells?

:-)