Annales seu Cronicae Incliti Regni Temeriae, which roughly translates to "Annals or Chronicles Celebrating Temerian Rule", is a tome written by Jarre sometime after the war with Nilfgaard which talks about the Battle of Brenna.
Thus in all the historical and military literature it became customary only to write the Battle of Brenna–both in the North, and in Nilfgaardian sources, of which, nota bene, there are many more than ours.
Annales seu Cronicae Incliti Regni Temeriae
The centre of the royal formation stood beside a hill later to be named Gallows Hill. There, on the hill, stood with their detachment King Foltest and Constable Jan Natalis, having a prospect of the whole battlefield from high up. Here the main forces of our army were gathered–twelve thousand brave Temerian and Redanian infantrymen formed in four great squares, protected by ten cavalry companies, standing right at the northern end of the fishpond, called Golden Pond by local folk. The central formation, meanwhile, had a reserve regiment in the second line–three thousand Vizimian and Mariborian foot, over which Voivode Bronibor held command.
From the southern edge of Golden Pond, however, up to the row of fishponds and a bend in the River Chotla, to the marches a mile wide, stood the right wing of our army, the Volunteer Regiment formed of Mahakam dwarves, eight companies of light horse and companies of the eminent Free Mercenary Company. The condottiero Adam Pangratt and dwarf Barclay Els commanded the right wing.
Field Marshal Menno Coehoorn deployed the Nilfgaardian Army opposite them, about a mile or two away, on a bare field beyond the forest. Iron-hard men stood there like a black wall, regiment by regiment, company by company, squadron by squadron, endless it seemed, as far as the eye could see. And, from the forest of standards and spears, one could deduce that it was not just a broad but a deep array. For it was an army of six and forty thousand, which few knew about at that time, and just as well, because at the sight of that Nilfgaardian might many hearts sank somewhat.
And hearts started to beat beneath the breastplates of even the bravest, started to beat like hammers, for it became patent that a heavy and bloody battle would soon begin and many of those who stood in that array would not see the sunset.
And thus they fought, truly like the sea against a rocky cliff, thus continued the battle in which you could not guess who had the upper hand, for although the waves endlessly beat against the rock, not weakening, and they only fell back to strike anew, the rock stood on, as it had always stood, still visible among the turbulent waves.
The battle unfolded in a different way on the right wing of the royal army. Like an old sparrowhawk that knows where to stoop and peck its prey to death, so Field Marshal Menno Coehoorn knew where to aim his blows. Clenching in his iron fist his select divisions, the Deithwen lancers and the armoured Ard Feainn, he struck at the junction of the line above Golden Pond, where the companies from Brugge stood. Although the Bruggeans resisted heroically, they turned out to be more weakly accoutred, both in armour and in spirit, than their foes. They did not weather the Nilfgaardian advance. Two companies of the Free Company under the old condottiero Adam Pangratt went to their aid and held back Nilfgaard, paying a severe price in blood. But the awful threat of being surrounded stared the dwarves of the Volunteer Regiment standing on the right flank in the face, and the severing of the array imperilled the whole royal army.
And Field Marshal Menno Coehoorn understood that the battle was lost, saw the brigades perishing and falling into confusion around him.
Thus did Brenna become the beginning of the end. But it behoves me to write that that battle was but a small stone in the building, and superficial would have been its importance had the fruits of the victory not been wisely taken advantage of. It behoves us to recall that instead of resting on his laurels and bursting with pride, and awaiting honours and homage, Jan Natalis headed south almost without stopping. The cavalry troop under Adam Pangratt and Julia Abatemarco destroyed two divisions of the Third Army that had brought belated relief to Menno Coehoorn, routing them such that nec nuntius cladis. At news of this, the rest of the Centre Army Group took miserable flight and fled in haste to the far side of the Yaruga, and since Foltest and Natalis were on their heels, the imperial forces lost entire convoys and all their siege engines with which, in their hubris, they had meant to capture Vizima, Gors Velen and Novigrad.
And like an avalanche rolling down from the mountains, becoming covered in more and more snow and becoming greater, so also Brenna caused more and more severe results for Nilfgaard. Hard times came for the Verden Army under Duke de Wett, whom the corsairs from Skellige and King Ethain of Cidaris sorely vexed in a guerrilla war. When, meanwhile, de Wett learned about Brenna, when news reached him that King Foltest and Jan Natalis were marching briskly to him, he immediately ordered the trumpeting of the retreat and fled to Cintra, strewing the escape route with corpses, because at the news of the Nilfgaardian defeats an insurrection in Verden flared up anew. Only in the undefeated strongholds of Nastróg, Rozróg and Bodróg did powerful garrisons remain, for which reason only after the Peace of Cintra did they leave honourably and with their standards intact.
Whereas in Aedirn, the tidings about Brenna led to the feuding kings Demavend and Henselt shaking each other's right hands and taking arms against Nilfgaard together. The East Army Group, which under the command of Duke Ardal aep Dahy marched towards the Pontar valley, did not manage to challenge the two allied kings. Strengthened by reinforcements from Redania and Queen Meve's guerrillas, who had cruelly plundered Nilfgaard, Demavend and Henselt drove Ardal aep Dahy all the way to Aldersberg. Duke Ardal wanted to give battle, but by a strange twist of fate he suddenly fell ill, having eaten something. He came down with the colic and diarrhoea miserere, and thus in two days he died in great pain. And Demavend and Henselt, without delay, attacked the Nilfgaardians, also there at Aldersberg, evidently for the sake of historical justice, and they routed them in a decisive battle, though Nilfgaard still had a significant numerical advantage. Thus do spirit and artistry usually triumph over dull and brutal force.
It behoves me to write about one more thing: what exactly happened to Menno Coehoorn himself at the Battle of Brenna no one knows. Some say: he fell and his body, unrecognised, was buried in a common grave. Others say: he escaped with his life, but fearing imperial wrath did not return to Nilfgaard, but hid in Brokilon among the dryads, and there became a hermit, letting his beard grow down to the ground. And there shortly after expired amidst his worries.