The two battles took place in the third and final war which Prussia fought against the Habsburg Empire under Maria Theresa for control of Silesia. They also formed part of a much wider conflict, the Seven Years' War, in which Britain, Hanover, with which it was united, Portugal and some smaller German principalities sided with the Prussians, and France, Russia, Spain, Sweden and Saxony with the Austrians. Because of the participants' interests outside Europe, the conflict spilled over into North and South America, Asia and Africa. A few months before Rossbach and Leuthen, Robert Clive's defeat of the nawab of Bengal and his French allies at Plassey had laid the foundations for British rule in India.

That year was the bloodiest of the 18th century. In six big battles — Prague, Kolin, Gross-Jägersdorf, Rossbach, Breslau and Leuthen — it is estimated that, among the 560,000 who took part, losses amounted to 120,000. It would take until 1809, the date of Wagram, for that total to be exceeded. 

At Rossbach on November 5, Frederick, with 22,000 men, defeated an allied force (France, the Reichsarmee of the Holy Roman Empire, and Austria) of about twice that size. Differences between incompetent enemy commanders, the Prince de Soubise, a favourite of Madame de Pompadour, and the Prince von Sachsen-Hildburghausen, made the king's task easier. But, having been surprised by an allied flanking movement, the Prussians and their allies quickly redeployed and, hiding behind undulations in the terrain, caught the head of the advancing columns in a pincer movement. Cavalry and cannon, arms which Frederick had strengthened after years of struggle with the Austrians, played a dominant part. 

The artillery commander, Colonel Karl Friedrich von Moller, opened the engagement with heavy ordnance which he later succeeded in manoeuvring to a second location. The cavalry, led by Major-General Friedrich Wilhelm von Seydlitz, charged after the first cannonade, met stiff resistance but managed to reassemble before the end of the battle and deliver the coup de grâce. In less than one-and-a-half hours the allies had lost over a fifth of their men and more than 70 per cent of their artillery. On the other side the losses amounted to less than 3 per cent of total forces. Franz Rudolph Mollinger, secretary to one of the allied commanders, wrote that Frederick "could justifiably count this victory as the most economical — but at the same time the most remarkable...and rewarding — ever attained by his arms".

The battlefield today is largely unchanged, except in one crucial aspect. The manor house in Rossbach where Frederick was lunching with his officers as the allies advanced still stands, and his stay is commemorated in a relief over the front door. You can see the ridge above the Leiha stream on which the Prussians, facing west, first deployed, and the southern line of hills, commanding a view over the village, along which the allies advanced. But the core of the battle site has been heavily degraded by brown coal mining. The Janus Hill, a gentle eminence behind which the Prussians concealed themselves, has been removed, giving way to a large artificial lake.