Complex sentence: On the evening of January 4, a mob of armed white men went to Rosewood and surrounded the house of Sarah Carrier, which was filled with approximately 15 to 25 people seeking refuge, many of whom were children hiding upstairs under mattresses.
Split into simpler sentences: On the evening of January 4, a mob of armed white men went to Rosewood and surrounded the house of Sarah Carrier. It was filled with approximately 15 to 25 people seeking refuge, including many children hiding upstairs under mattresses.