The St. Cecilia window is dedicated to the Glory of God and in loving memory of Joseph and Emma Agg and their family. Joseph Agg was organist and choir director at All Saints’ from 1919–1926, Emma was an active member of the choir and the Woman’s Auxiliary.
The window is rich and warm in its varying shades of cream, gold, green, and brown. The bright golden organ occupies the right foreground of the window and is commanding in its mass and brilliance. The angel rising in the upper back third of the window is dramatic and eye-catching. The compression of its wings in the arch of the window creates the impression that the grandeur of this angel is barely contained within the scene. The subject of the window, St. Cecilia herself, occupies the left-hand portion of the window. The nimbus and red shawl collar of her cloak serve to frame her lovely face.
Conspicuously central to the window, in the space between these three major elements — the saint, the organ, the angel — is Cecilia’s single upraised hand. Her fingers are elegantly outstretched and her thumb slightly crossed over her palm as if she has just raised her hand from the keyboard. Consider also the tilt of her jaw and the way she is glancing sideways and upward toward the angel. This is no question that this central gesture is that of a conductor, perhaps cueing her trumpeter to an entry or maybe a tempo change in her song. How fitting a memorial for a music director.
In her time (c 200 AD), Cecilia was a cultivated young Roman woman who vowed her virginity to God. On her wedding day, “as the musicians played, she sang in her heart to God only” (cantantibus organis illa in corde suo soi domino 
decantabat). Cecilia told her new husband, Valerian, that she was accompanied by an angel, and in order to see it, he must be baptized. Valerian and his brother were converted and later martyred for their faith. Cecilia was also killed. Some accounts indicate that as she was dying, Cecilia again sang in her heart to God. By the 15th century, St. Cecilia was declared Patron Saint of musicians, poets, and church music. In art, she is most often depicted playing the organ and accompanied by cherubim or an angel. Palms, a symbol of martyrdom, and lilies, the flowers of purity, also often appear in St. Cecilia depictions. Not surprisingly, St. Cecilia windows are usually situated in choir lofts, music rooms, or near to the organ.
A final notable feature of this window is the last line of the dedication: “Given by the late Ronald Agg 1985.” It was Ronald Agg, Joseph and Emma’s youngest son, who spearheaded the arrangements for the window’s creation and installation. He did not live to see it dedicated.