Hildegard of Bingen is commonly acknowledged as one of the greatest polymaths of the Middle Ages. An encyclopedist, poet, and composer, the 12th-century abbess wrote prolifically and imaginatively, leaving a prodigious output that still astounds historians. Frank Ferko, who holds a PhD in composition from Northwestern University, has long been fascinated by her accomplishments. In the last few years he and Barbara Newman, a Northwestern prof, have stirred up enough interest in Hildegard to turn her into a cult figure. Ferko's organ cycle based on Hildegard's chants, which premiered two seasons ago, first drew attention to her keen musical mind. The second of his trilogy, the Hildegard Motets, commissioned by His Majestie's Clerkes to commemorate their tenth-anniversary, ought to do the same for her poetry. Hildegard wrote at least 72 sacred poems (in Latin), most of which she also set to music for church services. Ferko, who says he's awed by their pious beauty, picked nine as settings for his own motets, each marking an important occasion in the Christian liturgical calendar. These a cappella pieces, tailored to the Clerkes' well-schooled voices, are written in a style much influenced by the religious music of Poulenc and Messiaen. Anne Helder, herself an excellent musicologist, directs the choir. A brief talk on Hildegard by Newman precedes the concert. Sunday, 7:30 PM, Three Arts Club, and next Sunday, June 20, at 7:30 PM, Church of Saint Paul and the Redeemer, 4945 S. Dorchester; 708-866-7464.