Complex sentence: This was seen at the time as a major cultural outflow as many of the books were of historical and cultural significance-additionally the society's library had received an annual grant since 1945 for the upkeep of the books from the Irish Exchequer.
Split into simpler sentences: This was seen at the time as a major cultural outflow as many of the books were of historical and cultural significance. In addition, the society's library had received an annual grant since 1945 for the upkeep of the books from the Irish Exchequer.