Provenance Details Depicted in Manuscripts Depicted in Paintings

I've been in Belgium most of the week, to see the Van Eyck exhibition in Ghent, so have not had time to write the usual blogpost.  Apart from the exhibition, one of the most interesting things I saw was an exceptionally detailed depiction of two Books of Hours in this pair of early 16th-century Flemish portraits, of Lievin van Pottelsberghe (d. 1531) and his wife Livina van Steelant (d. 1563):

The books are painted with such detail that one can see their heraldry and read their mottos.

His arms show a red-stringed silver hunting-horn on a black ground, with a gold band at the top, and his motto is "PLUS EST EN LUY":

(rotated)

Her arms are dimidiated with those of her husband on a lozenge-shaped field, her motto is "MA FOY EST TELLE", and one can even read the text of the prayer above:

"Ave sanctissima Maria mater dei templum trinitatis ..." (rotated detail)

Galleys of a recent article about the paintings can be downloaded from Academia.edu: Frederik Buylaert et al., 'The Van Pottelsberghe-Van Steelant Memorial by Gerard Horenbout: Lordship, Piety and Mortality in Early Sixteenth-Century Flanders', Zeitschrift für Kunstgeschichte 4 (2014), pp. 491-516.