Complex sentence: On 9 November, a few days after the battle of Valmaseda, at which it did not take part, the Dutch brigade reached Valmaseda, which was in the process of being sacked in reprisal for the murder of three Frenchmen.
Split into simpler sentences: On 9 November, a few days after the battle of Valmaseda, at which it did not take part, the Dutch brigade reached Valmaseda. It was in the process of being sacked in reprisal for the murder of three Frenchmen.