Mieszko I of Poland before his death among a number of princes. They were probably his sons: Bolesław I the Brave, Mieszko and Lambert. In 1999 the archeologist Hanna Kóčka-Krenz located what's left of Mieszko's palace-chapel complex in Poznań. The basic structure of the early Polish state was Mieszko's military force. The ruler managed to create an army composed of about 3,000 mounted warriors. This increasingly powerful force allowed the Polans to attack weaker neighboring tribes and conquer their lands. A key factor promoting cohesion of the growing state was fear of the invaders impressed by them among local populations. The first Piasts reinforced
Mieszko I, Duke of Cieszyn The Obituary of the Church of St. Vincent in Wrocław showed the existence of a certain "Grzymisława, Duchess of Opole" ("Grimizlaua ducissa Opuliensis") who was buried there around 13 September 1286. Her parentage is also unknown, but her name suggests a Russian origin, probably member of the Rurikids. Her title suggests that she may have been the wife of Mieszko I or the first wife of Bolko I (Mieszko I's brother), or maybe a completely different person. Also, the exact date of their marriage was uncertain, but after a further reconstructions of their children's birth dates, was placed between 1275