In 2006, King's College, London, purchased a collection of colour propaganda
posters from the Moravian Church of North America. The posters were
collected by the Reverend Kenneth G Hamilton (1892-1975), while working
as a YMCA chaplain during World War One, and at some stage were placed
with the Moravian Church. You can see them on their very interesting WW1 collections here, which will doubtless reward a little exploration.