Another class of knights were granted land by the prince, allowing them the economic ability to serve the prince militarily. A Polish nobleman living at the time prior to the 15th century was referred to as a "rycerz", very roughly equivalent to the English "knight," the critical difference being the status of "rycerz" was almost strictly hereditary; the class of all such individuals was known as the "rycerstwo". Representing the wealthier families of Poland and itinerant knights from abroad seeking their fortunes, this other class of rycerstwo, which became the szlachta/nobility ("szlachta" becomes the proper term for Polish nobility beginning about the 15th century), gradually formed apart from Mieszko I's and his successors' elite retinues. This rycerstwo/nobility obtained more privileges granting them favored status. They were absolved from particular burdens and obligations under ducal law, resulting in the belief only rycerstwo (those combining military prowess with high/noble birth) could serve as officials in state administration.