EAA Research Consultant
Join Date: Dec 2004
Location: Route 66
These swords were very much fashion accoutrements, and the chain was entirely decorative, not intended to be functional. The use of chains in place of knuckle guard was very common by the end of the 18th century, where the age of the small sword was closing, and hilt elements such as pas d'ane were entirely vestigial.
The chain is not a component which might be relied on for establishing date or any other factor. Such estimations are based more on the nature of the actual hilt structure and elements and design character. For example Dutch and English often run very closely, while French seem to have the subtle indicators which set them apart. I am certainly no authority on these, but have had the J.D. Aylward book for many decades, and this is about the best book to learn more.