Complex sentence: Although the notices were delivered peacefully for two days, a group of locals gathered on the evening of 13 December and a man wearing a sash warned the collectors that trouble would ensue if they returned the following day.
Split into simpler sentences: Although the notices were delivered peacefully for two days, a group of locals gathered on the evening of 13 December. A man wearing a sash warned the collectors that trouble would ensue if they returned the following day.