Salzburg was once under siege by enemy forces during the peasant insurrections around 1525. The massive stone walls of the town were virtually impregnable so the enemy had to find another way to conquer it. They planned to let the town starve until it was willing to surrender and encircled it with troops to prevent anyone from entering or leaving.
The Salzburg residents soon understood the enemy's intent. Although they had always relied on their fortifications until then, the situation caused them great concern. If the siege persisted, great famine would break out. The town's commander ordered his citizens to observe a strict fast. But one day only a single bull was left that had not been butchered. It had brown spots and was well-nourished.
The town commander devised a means of fooling the enemy. In the early morning hours the bull was driven onto the bastion so that it was readily visible to the enemy to indicate that the Salzburg population was far from starving. That night the Salzburg citizens painted the spotted bull white, only to display it to the enemy again the next morning. On the third morning a pitch-black bull strolled up and down the fortress wall. The enemy troops gazed in astonishment, thinking the town was still well-stocked and secretly retreated one dark night.
There was great rejoicing throughout the town. The citizens led the bull down to the Salzach and washed it until the brown spots on its coat became visible again. Ever since this time, Salzburg residents have been known as "Stierwascher" (Bullwashers).
That's how the popular legend is told. According to the historical facts, the Salzburg butchers had to slaughter the animals in public to prevent any contaminated meat from being sold. The customary practice of washing the animals on the shallow banks of the Salzach, which reached all the way up to the walls of the town, and the subsequent inspection of the meat caused Salzburg residents to be jokingly referred to as "Stierwascher."