Suspenders first made an appearance in men's fashion in France in the 1700s as ribbons attached to trousers. Suspenders were functional back when they were first invented. Due to the high-waisted nature of men's pants, belts were impossible to use and suspenders did the job of holding up trousers. Interestingly enough, according to "Time," "In fact, visible suspenders were considered risqué as recently as 1938...."
Suspenders are two thin pieces of knitting, crochet, fabric or leather material men wear connected to their pants in front and back and resting on the shoulders. Men use clips, buttons or fabric strips to attach suspenders to their trousers. Suspenders traditionally meet in back, forming a "Y," "H," "V" or "X" shape.
What you would recognize as suspenders came on the scene in the 1800s. Pioneers and soldiers made use of suspenders to hold pants out of mud and keep uniforms in proper order. Antique patterns for suspenders are popular nowadays among historians for period costumes, including Civil War reenactments.
Handmade suspenders of the 1800s were made from rough cotton, although "Godey's Magazine" included a pattern to use silk. The brioche stitch was a common element of knitted suspenders. Brioche stitching creates a crisscrossing pattern that resembles woven cotton braid. Sometimes, suspenders were not knitted at all, but were long-crocheted chains. The suspenders usually had buttonholes or pieces of leather at the ends for attaching to pants.