This structured organization gradually lost power over the course of the 10th and 11th centuries, as the Fujiwara clan, dominating the post of Imperial regent, began to dominate the "Daijō-kan" as well. It became increasingly common for the regent to hold the post of chancellor or other office simultaneously. By the 12th century, the council was essentially powerless as a separate entity, though it seems clear that the system was never formally dismantled. Over the course of centuries, the "ritsuryō" state produced more and more information which was carefully archived; however, with the passage of time in the Heian period, "ritsuryō" institutions evolved into a political and cultural system without feedback.