During the Bronze Age several burials were made in Denmark which have preserved clothing and accessories. Men of high status favoured semi circular caps in layers of cloth covered with tiny sewn and knitted threads to form a pile surface, and there are slightly simpler taller caps in heavily fulled wool cloth.
This plain hand felted pure wool version is an extrapolation, we don't have a specific example of a felted cap from Northern Europe in the Bronze Age, but it does offer the right general feel in shades of undyed black, grey or brown sheep's wool and draws additional inspiration from ancient Greek felted caps and also those surviving felted caps from the Tarim mummies in Asia. 
Made to order, so do let me know your head measurement and whether you'd like a shorter or taller version.
Second photo is a hat I made for the facial reconstruction of Ditchling Man by  Oscar D. Nilsson, and which can be seen in Brighton Museum.
As with all my made to order items, I take orders in batches and then make them over the next three to four months. Some orders get done almost straight away, others at any point within that timescale.