Complex sentence: The Czechoslovak delegates referred to it when arguing for the recognition of the new state; and official celebrations on the eleventh centenary of the mission of Constantine and Methodius in Czechoslovakia emphasized the continuity between the early medieval and the modern state in 1963.
Split into simpler sentences: The Czechoslovak delegates referred to it when arguing for the recognition of the new state. Official celebrations on the eleventh centenary of the mission of Constantine and Methodius in Czechoslovakia emphasized the continuity between the early medieval and the modern state in 1963.