Complex sentence: During the 1920s, short suits were always worn except on formal occasions when a morning coat would be worn for formal occasions in the daytime; old conservative men continued to wear a frock coat, or "Prince Albert coat" as it was known.
Split into simpler sentences: During the 1920s, short suits were always worn except on formal occasions in the daytime, when a morning coat would be worn. Older, more conservative men continued to wear a frock coat, or "Prince Albert coat" as it was known.