Complex sentence: This percentage calculation is based on the assumption that the 6 million figure includes the women and children of Roman citizens-technically, only adult (i.e. over 14 years of age) males were citizens.
Split into simpler sentences: This percentage calculation is based on the assumption that the 6 million figure includes the women and children of Roman citizens. Unfortunately, this is not certain: technically, only adult (i.e. over 14 years of age) males were citizens.