I went to hear Sequentia, one of the world's premiere Early Music ensembles (well, duo for this performance), perform in Houston last Sunday. The program was of musical fragments of German, Old English, and Nordic 9th-11th Century End of Time texts. The setting was the Rothko Chapel in the Menil compound area.
The Executive Director of the Rothko Chapel came out before the performance and briefly discussed the meaning and purpose of the Rothko Chapel (with its giant black and dark grey canvasses). She described it as "sacred space designed for spiritual contemplation," and as part of Mark Rothko's vision and intent. It has holy books from all the World's major (and not so major) religions, suitable for the quiet contemplation/worship of the god(s) of one's own choice (or of Mark Rothko).
Rothko himself saw the chapel to be a Roman Catholic institution, based upon an Eastern Orthodox chapel. His monochrome paintings were meant to be references to the crucifixion of Christ. Dominique de Menil had other, more ecumenical, thoughts.
Mark Rothko committed suicide before the chapel was completed.