Complex sentence: However, the following April, he opposed Edward's landing at Ravenspur and joined forces with the Duke of Exeter but they were too weak and were forced to stand aside at Newark and allow Edward to march south to London.
Split into simpler sentences: However, the following April, he opposed Edward's landing at Ravenspur. He joined forces with the Duke of Exeter, but they were too weak and were forced to stand aside at Newark and allow Edward to march south to London.