Complex sentence: During the 17th and 18th centuries, this meal, called dinner, was gradually pushed back into the evening, creating a greater time gap between breakfast and dinner; a meal called "lunch" came to fill the gap.
Split into simpler sentences: During the 17th and 18th centuries, this meal, called dinner, was gradually pushed back into the evening, creating a greater time gap between breakfast and dinner. A meal called "lunch" came to fill the gap.