Complex sentence: Undeterred by the severe wounds which he had received, and seeing no prospect of active service with the British fleet, Willoughby offered his services in 1812 to the Russian government, and while serving with the Russian army he was captured by the French.
Split into simpler sentences: Undeterred by the severe wounds which he had received, and seeing no prospect of active service with the British fleet, Willoughby offered his services in 1812 to the Russian government. While serving with the Russian army he was captured by the French.