Cushions for chairs were first popular in the Middle Ages. These cushions were decorative and were a status symbol of the wealthy. They were usually made of leather too. As the centuries progressed, the cushions began to be made of other fabrics as well, such as tapestry. You can make your own back cushion with the fabric or material of your choice.
Decide of the dimensions of the back cushion and buy a piece of 1/2 inch foam in those dimensions. If you are unable to buy a piece of foam that is of the size that you wish, buy a piece of foam that is of the thickness that you need and then cut it to size. Buy fabric that is two and half times the size of the dimensions of the pillow. Buy thread that is of the same colour to the fabric or that will compliment it as well as straight pins.
Prepare the back cushion cover
Cut the foam to size if that has not been done already. Cut open a paper bag and trace around the foam to create a pattern. Cut out the pattern piece. Fold the fabric in half, right side to right side. Pin the paper on the fabric and trace around it with tailor's chalk. Trace around it again adding 1/2 inch for seam allowance. Cut out the fabric. Create a flap for the cushion by cutting a piece of fabric that is of the width of the back pillow cover and of four inches wide. Pin the flap to the top of one of the fabric pieces, right side to right side, and sew them together. Lay the fabric pieces for the back cushion together. Sew along the sides and bottom, leaving the top and the portion where the flap is sewn open.
Create the back cushion
Turn the cover for the back cushion right side out. Slip in the foam into the cushion and tuck the foam inside the flap. You can add details to the cover of the back cushion by adding cording and other decorations. To add the cording, pin it in between the fabric pieces pointing in toward the middle of the cover. When you turn the cushion cover right side out, the cording will extend beyond the edges of the fabric.