This leaf has several illuminated letters, primarily in orange and blue, and a border that extends more than halfway across the top and bottom of the columns and completely down the left side. The design is filligreed and the text is in an unidentified language.
Judging by its distinctive ‘block’ penwork, this is a leaf from a book of hours made in the present day Netherlands, i.c. Delft, convent of St. Agnes, c. 1475. Likely from a book formerly owned by Philip van Alfen, sold (when still complete) at Sotheby’s in 1972 and Christie’s in 1986. Afterwards brutally dismembered; leaves now scattered all over US and Europe.
Thanks for sharing these details! I’ve shared your remarks with a group that’s trying to bring scattered manuscripts like this back together: https://peripheralmss.org/