Complex sentence: The most prestigious toga of all, the embroidered purple "toga picta", could only be worn by the highest ranking civil authorities (magistrates), elected annually from the Roman aristocracy, whose customary aristocratic privileges and prestige were protected by sumptuary laws.
Split into simpler sentences: The most prestigious toga of all, the embroidered purple "toga picta", could only be worn by the highest ranking civil authorities (magistrates). They were elected annually from the Roman aristocracy, whose customary aristocratic privileges and prestige were protected by sumptuary laws.