If you study a modern English-language history of the Peninsular War - and Charles Esdaile's book is a particularly good example - you get an impression of that conflict which would have been barely recognisable 50 years ago.

It seems unbelievable now, but my original plan for my wargame armies for the Peninsular War had no Spanish troops on either side. Laughable might be a better word. There were reasons. Partly it had to do with the availability of suitable miniatures in the correct scale (20mm or old-fashioned 25mm - basically "1-inch" figures), but it is also true that the overwhelming impression I gained from my reading prior to (say) 1975 was that this was appropriate. I had read and re-read Michael Glover's "Wellington's Victories in the Peninsula", and moved on to his more substantial "The Peninsular War 1807-1814" when it appeared in 1974. Looking at it again today, it is remarkable. Considering that Glover freely acknowledges that his main source was Oman's multi-volume tome, it does make you wonder what happened to all the Spanish bits. The narrative strings together the campaigns of the British troops (with some reference to their integrated Portuguese allies) and of the French armies which were specifically engaged in opposing them. Thus there is only fleeting reference to the other French armies (virtually nothing about the crucial fighting between Suchet and the guerrilla forces in the north, for example), and the Spaniards appear only rarely, and in cartoon form. Cuesta is portrayed as a character straight out of Punch and Judy, and the performances of the Spanish field armies are mentioned only when they support the general themes of incompetence and disorganisation. The cataclysmic Spanish success at Baylen is covered in two short paragraphs, and - to restore balance - Castaños is described as "one of the few Spaniards of talent".
You get the idea. This polarised view of history was supported by Jac Weller's "Wellington in the Peninsula" and by what I had seen of the classic work by Napier. The Spanish guerrillas were effective (if distressingly given to barbaric vengeance), but the real war was between Wellesley/Wellington and the French Army of Portugal. This was the received British view of the Peninsular War.
Because of the shortage of pre-1812 wargame figures, I was pretty much committed to the later stages of the war, and I took Salamanca as my period of choice. Admittedly there were some Spanish troops in the Allied army at Salamanca, but they did not play a major part, I could find little or no reliable information about either their organisation or their dress, and the writings of Messrs Featherstone and Co suggested very strongly that no-one would actually choose to command a Spanish force anyway. So though I did pencil De España's division into my proposed OOB, I had no thoughts really on how to set about recruiting it.
Since my return to wargaming this period in recent years, I find that the histories now give a much wider view, and that it is now generally accepted that the Spaniards did much more than merely providing a location and an excuse for the British and the French to fight each other. I have done a lot of work on researching and building Spanish contingents for both sides, still taking my base year as 1812. It is a lot easier now.
The Nationalist Forces
None of this would ever have been possible if I hadn't obtained a copy of JM Bueno's fine "Uniformes Españoles de la Guerra de Independencia", which is a real reference bible. In the scales I use, only Hinton Hunt and Minifigs (I can use some S-Range figures) made Spanish infantry in the British supplied 1812 uniform. Since I was dissuaded from selling the house to raise funds to purchase HH (which, strictly speaking, are a tad small for me anyway), I managed to collect together enough Minifigs SN1s figures to put together some battalions. Partly this was achieved though some swaps which in some cases amounted almost to acts of charity - I am still very appreciative of everyone who helped. Most of my line units are SN1s, with mounted colonels converted from Art Miniaturen Belgians. The Cazadores de Castilla required a double-breasted coat with British light-infantry style shakos, so Falcata French infantry were fitted with Higgins British LI heads. Because I could not get hold of enough S-Range infantry, I also have a battalion of Warrior figures. They are OK, but I'll replace them if I can get more of the Minifigs. There's something about Warrior - if you measure them they should be reasonably compatible, but somehow they don't look quite right. Also, they always have that lunging stance which causes visitors to say, "Ah - I see you have some Warrior infantry - what unit is that?".

Regiments of Sevilla, 2nd Princesa and Jaen, with, in the foreground, the Tiradores de Castilla (left) and Cazadores de Castilla.
I have also added a battery - the gunners are uniformed in the French style - not least because the castings are NapoleoN French foot artillery. The officer is Art Miniaturen.
My generals are as yet unpainted - they are in the pipeline. I would like to add some cavalry, but am still looking for suitable figures. Warrior do make lancers, but they have a touch of Picasso’s Don Quixote about them which makes it hard for me to take them seriously, and Warrior's own horses are too like Bucephalus to fit in. There were (very briefly) some terrific Falcata lancers, available a couple of years ago, but I missed those (of course).
I'm now working on a militia brigade to add to this organisation - 4 battalions plus a battery. Castings are NapoleoN and more Minifigs S-Range, and I hope to obtain a battalion's-worth of Kennington's 1812 American militia, which look to me like a good prospect for a nation switch. I'll put some pictures up here when the militia are painted and ready for action.