That's what.
This is from the Lindisfarne Gospels. It is from one of the pages just before Saint Luke’s Gospel begins.
In the Book of the Prophet Ezekiel (Chapter 1) and in the Book of Revelation (Chapter 4) there are visions of four winged creatures.
In Christian art and symbolism these have been interpreted as the four Gospel writers.
One of them – the winged Ox – is taken to be Saint Luke.
Saint Luke wrote a Gospel and the Acts of the Apostles.