Skills with Quills.
Thomas, the scribe, was fortunate enough to have learnt his trade and skills with quills and parchment while in service as a young man with the Arundel family on their estates in Devon and Cornwall and now finds a role as both a scribe and a soldier with Sir Fitz Arundel.
This combination of roles is not unusual in these troubled times and Thomas has deadlier skills to offer with the crossbow. While not as much in evidence as the longbow, the crossbow is, in the right hands, a lethal weapon and finds it's place in areas such as defence in confined spaces. This is not to say that Thomas is not willing and capable of taking up the longbow when necessary.