Old wooden medival/renaissance era chairs with leather laces and steel rivets

I aquired these chairs from the attic of an old German bar/resturant that has been around for over 50 years. I have 12 of these chairs in my possession. Chairs do have damage. Some are wobbly. Some have broken/torn leather laces. Some are mising steel rivits. Chairs are solid without any major cracks or damage. Chairs are made of wood (type unknow), leather laced and have steel rivets. Chairs could use a good cleaning but would make an excellent addtition to any room of this period. I have no idea when, where or who made these chairs and would like any information possible along with possible appraisal. Chairs are for sale...