Fur can be tricky, so here’s some help on the way if you are going to fur line your garment (like this late 15- early 16th century gollar).
I don’t know how the fur lining were made historically, but I am guessing that you either treated the fur like a garment of your own (sew the fur together to a garment, then attach it to the outer fabric) or as a fabric lining (cut out the pieces of fur and stitch it to the seam allowances of the outer fabric once this is sewed together). A mix of these two might also be the case, due to the different challenge you face when fur lining a garment without it getting bulky.
If you only want a strip of fur on your garment, I find it easiest to cut out the fur pieces, and treat them like fabric lining; cut them straight and clean, join small bits if necessary before sewing them to the outer fabric. In contemporary art the fully fur lined garment seems to be the most common one, it is more like you could interpret some pictures as only having trims in fur. Fur was both fashionable and warm and used in many garments, and I have a fully lined gollar. This one becomes to warm during summer, and also take a lot of space in the bag when packing, so I though this new one would be a good alternative; fashionable, with the fur to warm me against wind, but lighter in both warmth and packing space.
I started with my wool gollar; I cut out the main piece and the collar, and sewed them together with running stitches. The most common thread for the period seems to be uncoloured linen thread, so I used unbleached linen that I waxed to make it more durable while sewing. After the pieces were joined together, I pressed down the seam and cut down the seam allowance on one side, to get a laid down seam. This makes the seam more smooth, and adds durability to the garment.
I tried to lay the gollar out flat, for you to get a good look. Note that it is not a full circle, you want it to lay flat against your back and shoulders in a tight fit. The fit on the gollar you’ll have to try out for yourself; so make one out of scrap fabric if this is your first one.
I then measured the collar and the front where I wanted the fur to be, and cut out strips of fur to match them. I then sewed them into place with linen thread and a small, regular needle. A thinner needle makes it easier to sew in fur, and pinning the fur into place makes sure it doesn’t stretch or slides.
At the corners I just sew the fur to the fabric, and leave the left over fur for later. Note that I treat the fur like fabric; sewing the furry side to the right side of the fabric.
When the fur is sewn onto the fabric, I cut away the left over and trim the edges down.
At the corners I trim away enough fur so when I fold the fur inside the garment it will not get bulky but fit together edge to edge.
At the bottom edge I want the fur to follow the curved front of the gollar, so I mark this with a pen, and then cut it away.
After trimming down the fur, I fold it to the inside of the gollar, and pin it in place. Make sure it lays flat when wearing the garment; fur can be tricky and does not adjust the way fabric do. When you are happy with the fit, sew the fur in place with whip stitches, or attach it to a lining. In the corners the two pieces of fur should barely meet, the hair will hide the seam, so just sew them together loosely.
I chose to have a lining inside my gollar in a thin woolen fabric, to add warmth, make it easier to sew the fur down with no visible stitching, and because a fully lined gollar can be seen in art. For the lining, I cut out another gollar, without collar (because the fur strip for that part covered the inside of my collar) and without the parts that would be covered with fur. When fastening the lining in the gollar, pin it in place and then sew it at the same time as you attach the fur on the inside. Start with the collar, and then the front opening going down.
Sewing in fur is time-consuming and quite tiring for the fingers. Nice company or a movie is good to have!
When the fur (and lining) is attached around the gollar I stitched the lower hem with whip stitches. To make the seam smooth, I cut away some excess lining fabric, as can be seen at the photo. So; adjust the lining, cut of excess seam allowance, pin and whip stitch.
To fasten the gollar you can use dress pins, small fabric strips, ribbons or lucet braided strings, hooks and eyes or do as I did; add a fancy clasp at the throat. At the end of the sewing I didn’t really like that the fur was so visible at the bottom, so I trimmed it down quite hard. Another option would have been to let the fur finish on the inside of the gollar, so it was not so obvious that the gollar was not fur-lined all the way around. Cheating is hard sometimes…
The clasp is a late 15th century find from Sweden, with A standing for “amore”. It added nicely, but for a commoner a hidden fastening would do better.
A note about fur; I recommend you to put some thought and money into the purchase of fur. There are still many fur-fabrics and farms that treat animals like shit, where the animals suffers greatly to become your hobby-based garment. If you buy rabbit skin for 7-9 Euro/skin you probably support these farms, even if not buying directly from them. A better option would be to buy fur from local farms where you can visit the animals, and get to leave the skin at the tanner yourself. You can also find good choices on internet, buy second-hand or choose fake-fur from the fabric store (not the most historical accurate, but I rather go modern than use unethical furs)
Some examples of gollars being worn by 16th century common people during dances. Some of them clearly seems to have a fur line around the hem as being fur-lined, while others could be unlined or lined with fabric.