Complex sentence: Italian immigration to Tunisia had grown very rapidly under the French Protectorate, and by 1900, Italians made up approximately seven-eighths of the colony's European population of 80,000 people.
Split into simpler sentences: Italian immigration to Tunisia grew very rapidly under the French Protectorate. By 1900, Italians made up approximately seven-eighths of the colony's European population of 80,000 people.