In this article I bring together some of the distinguishing features of some Crux variants of Æthelred II. Some of these variants are hard to distinguish, so I have created a flow diagram that groups the coins by features that are shared in common. The article focuses on Crux, Early Transitional Crux, Late Transitional Crux, Small Crux and Intermediate Small Cross-Crux mules. This guide should aid people in identifying some of these coins. The descriptions of each coin type is not exhaustive, and variations will likely crop up that don’t always fit into these neat categories, but the key distinguishing features have been listed.
A Guide for Identifying Some Variants of the Crux Penny of Æthelred II – W.M.D. Castle
BNS Research Blog 
Nice article, one point my studies and practical experimentation on die life shows that for a typical die set (one obverse and two reverses) the reverse dies are capable of 20-30,000 coins each and the obverse of 60,000+ coins my findings are currently being written up for part III of my articles on die production and die life.
Hi David, thanks for the comment. What you mention is something that is incredibly interesting and the focus of a lot of debate. The current thinking at the moment is that late Anglo-Saxon dies could produce up to 20,000 coins. These estimates however, are typically based off of later medieval dies. Without knowing the exact methods of die production used by Anglo-Saxon smiths, it is hard to get a definitive answer. One thing I do know, is that there is a lot of variation in the hardness of different dies, depending on how they are produced (a William I die has been shown to be around 3 times harder than one of Cnut for example). This would obviously have an impact on the number of coins produced. If we took your highest estimate of 30,000 coins, and took the highest estimates of crux dies (let’s say 7000), we would be looking at an enormous 210 million coins – which seems excessively high! There are a lot of draw-backs to making estimates like this though, as we don’t know if every die was used until completely worn-out. We can assume that was the case at the largest mints where demand for coin was constant, but not necessarily at the smaller mints. I look forward to reading your article! I will keep an eye out for it.
King of Northumberland skeet silver
Evening Will, is it possible to show the identification marks you talk about in the flow chart? When you talk about double fold… on mine I have double folds across his shoulder but only 1 pleat hanging down! So not sure which folds your on about? Sorry. I’m but a simple man
Hi Mark, I think the easiest option would be for you to email me a picture and I can try to annotate it and can try and help you further. It has nothing to do with your intelligence! It took me a long time to work out what on Earth the literature was talking about with all these differences. Drop me a picture to: wcastle14@gmail.com
Thanks,
Will
Cheers Will