(GRADUAL LEAF.) Illuminated vellum leaf with liturgy for Saturday before Passion Sunday, with 7 lines of text written in Gothic hand in black ink

(GRADUAL LEAF.) Illuminated vellum leaf with liturgy for Saturday before Passion Sunday, with 7 lines of text written in Gothic hand in black ink beneath 5-line staves in red with square notation in black, recto and verso, with initial s in red and blue with intricate contrasting penwork decoration. 535x395 mm. later 15th century?