The tassels are, I would say, still pre-1850s, as the dyes used are natural dyes - the blue has faded to white in exposed areas, while the green has turned yellow (the blue overdye having faded). This points to the use of indigo, and certainly before the invention of chemical green.
I have decided that I will do a sympathetic repair and clean - some parts are obviously very dusty. This will mean that where ever possible, I will salvage the original decorative cords which decorate the various elements. However, all of the silk covering the wood has worn away on the exposed edges, so each element has to be picked apart in order to salvage the cords that remain, as they are laid over the worn silk. You can see what I mean in the photo below -
The gold coloured cord is in fair condition (although worn in some areas of the gimp) and so should be able to be salvaged by removing, gently brushing, and turning over so that the unworn underside is now exposed.
In this way I hope to be able to supply finished, useable tassels, which retain as much of their original elements as possible, without actually making new tassels in the style of.
The main cords have also become very worn - the silk covering each element has worn away from the core threads in most areas. However, they are still very strong, and the core threads are, in the main, dyed to similar shades as the original silk, so the overall impression is still of colourful, complicated cords. Because of this, I will retain the original cords.
The cords which decorate the various elements of the tassel really do show the extent of the cord winders art - these tiny cords are so delicate and tightly twisted! Most of the white cord however if very badly worn - broken in many cases. So, this will have to be replaced, by spinning my own gimp and cord. It is interesting about the white having so much damage, despite being so well made - I suspect that it has something to do with the bleaching process of silk. I've seen this same type of damage on a piece of medieval fringe in the V&A; the white silk was broken and worn away to a much greater extent than the blue and red fringes.
I will post up details and pictures as work, as I feel that much of this project will be a real learning exercise.