During the defense of Lithuania against the Teutonic Knights, he was given command of the castle in Kamieniec Litewski. The ruler was then impressed by his exceptional strategic abilities.

No wonder that when they were looking for commanders before Grunwald, Zyndram was remembered. The knight took part in arranging the military order and arranged the royal troops in troops and banners. On the day of the battle, he commanded the great royal banner on behalf of the king and the entire Polish-Lithuanian Commonwealth. It was the main body of the army, and it included select knights from all over Poland. During the battle, Zyndram led the Krakow banner into battle.

Did he leave Grunwald in glory and glory? Well, Zyndram's story ends as mysteriously as it began. Apparently, at one stage of the battle, he lost the king's trust and was stripped of his command. After the battle, he returned to his hometown and was no longer involved in public life. But what connects this knight with Golesz, before whose runes we stand? Well, there is evidence that this brave knight served in the castle as its starosta.