Complex sentence: On 22 July, he was arrested and imprisoned in the Luxembourg and on 23 July, the news came that Mainz had capitulated; on 28 July came the news of the loss of Valenciennes.
Split into simpler sentences: On 22 July, he was arrested and imprisoned in the Luxembourg. On 23 July, the news came that Mainz had capitulated; on 28 July came the news of the loss of Valenciennes.