Sounds like a fascinating book this!

In Londonderry, as in many other parts of the country, economic necessity as much as a sense of loyalty may well have been a factor in so many men from both the Protestant and Catholic traditions heading for the various battlefields of Europe. In recent years it has been revealed that almost 50 per cent of the names recorded on the City’s Diamond War Memorial hailed from the Catholic/nationalist community. But, with the advent of the Easter Rising in 1916 and again at onset of the Troubles in 1969 it is true that those from the Catholic tradition felt uncomfortable recognising or remembering the involvement of their ancestors in service to the Crown.

via ‘Remembering’- the city’s involvement in World War I – Londonderry Today.