Weissenstein — the modern Estonian town of Paide — sits on a low rise in the middle of a green, often soggy plain. Its medieval castle, built by the Livonian Order in the thirteenth century, was a strategic crossroads on the road between Dorpat (now Tartu) and Reval (now Tallinn). By 1604, control of central Estonia was the open question of the long Polish-Swedish War of 1600 to 1611, one front in a series of dynastic conflicts between the cousins Sigismund III Vasa, the Catholic king of Poland-Lithuania, and Charles IX of Sweden, the Protestant uncle who had pushed Sigismund off the Swedish throne. In the summer of 1604 a Swedish army of six thousand, led by Arvid Stålarm and the Spanish mercenary commander Alonzo Cacho de Canut, marched into Estonia and put Weissenstein under siege on 15 September. The first Swedish assault failed. The fortress garrison held.

Word of the siege reached Jan Karol Chodkiewicz, Field Hetman of Lithuania, who set out with a relief force ten days later. Chodkiewicz was already a veteran of two decades of border wars on the eastern and southern frontiers of the Commonwealth. He had a particular talent for using the Polish-Lithuanian winged hussars — heavy lance cavalry whose armored riders mounted long wooden frames bearing eagle feathers, a sight that was as much psychological weapon as decoration. The hussars were terrifying in the charge and disciplined enough to pull up, regroup, and attack again. With Chodkiewicz on this march were 2,300 of them and supporting infantry, against the Swedes' 6,000 — but he understood something about cavalry that the Swedes did not.

The battlefield Chodkiewicz arrived at lay between Dorpat and Reval, hemmed in by marshy streams east, west, and south. Stålarm placed his strongest unit, the German mercenary infantry under de Canut, on his left flank, anchored by a causeway and the road to Reval. The right flank, weaker but protected by the marshes, held the Finnish troops. Stålarm himself commanded the center with Swedish soldiers. De Canut, a careful Spanish professional, urged a loose Spanish-style formation. Stålarm, remembering how Polish hussars had repeatedly broken Swedish cavalry and then scythed through the infantry behind, mixed his cavalry and infantry together for mutual support. Across the field, Chodkiewicz read the deployment and made the unexpected call — attack the strongest wing, where the Swedish commander would not expect an attack to come.

The hussars went straight for the German reiters on the Swedish left and broke them in the first charge. Behind the cavalry, de Canut's infantry made the only fierce stand of the day, fighting hand to hand in the smoke until de Canut himself was killed. With his death the left collapsed entirely. Chodkiewicz wheeled his hussars and rolled up the rest of the Swedish line, pushing the surviving infantry into the marsh behind them. By the time the fighting ended, three thousand Swedes were dead, six guns and twenty-six standards captured (five of the standards destroyed in the fighting), and the entire Swedish baggage taken. The Polish-Lithuanian losses, according to the surviving sources: fifty killed, one hundred wounded. Even allowing for the usual victors' arithmetic, the disparity is staggering.

Stålarm's broken army withdrew. The siege of Weissenstein was lifted. Chodkiewicz would go on to win his most famous victory three years later at Kircholm in 1605, where 4,000 of his men routed an 11,000-strong Swedish army in less than half an hour. Modern Paide is a quiet Estonian county town of about ten thousand people. The hill where the medieval castle once stood is now Vallimägi park, with reconstructed walls and a modern observation tower built in the shape of the original keep. The marshy streams that ringed the 1604 battlefield have mostly been drained for farmland. From above, the country around Paide is a flat green table of fields and small forests, with the town itself a compact cluster of red roofs around the wooded hill — almost no hint of the day, four centuries ago, when three thousand soldiers died on its outskirts in two hours of fighting.