Reading
One book, several owners
Imagine removing the winged companion from Matthew’s Gospel miniature. A writer, manuscript and decorated border would remain. They would still suggest a Gospel portrait but would give you much less reason to choose Matthew over the other evangelists.
A fair question
A test showing an anonymous saint with a closed book cannot fairly force a choice between James the Less and every other apostle. Add a legible name from the frame or put the book in a documented series. The new information changes what the question can establish.
Checkpoint takeaway
Identify the evidence that would let a second viewer reach the same answer.
Visual study
The seated Matthew and his winged human companion occupy the miniature inside its decorated border.
Master of the Housebook · Cleveland Museum of ArtA large closed book occupies the lower right of the portrait.
El Greco · c. 1610–1614 · Public domain