There were a limited amount of ancestors venerated in the family temple but on the other hand, 70 generations of Kongs were buried in the cemetery meaning it was impossible to hold rites and rituals for everyone buried there. There were problems since some Kong nobles who held titles were buried outside of Qufu since they lived and died outside there, especially before the Song dynasty so there were no graves for them in Kong Lin. Some Kongs, and some of them Dukes had no direct descendants since they passed on their title to nephews, cousins or other relatives leading to uncertainty as to who should maintain their graves and clean them. And since in the 14th century Kong Sihui was given Kong Sicheng's title of Duke by the Yuan this implied that Kong Sichueng's father Kong Zhi wasn't a legitimate Duke and wrongly held the title so this brought the question if his grave should be given ducal treatment. In the 18th century, these questions concerning the cemetery were posed by Kong Jifen. He noted that actually nearly all pre-14th century graves before the generation of Kong Sihui had their locations lost in the historical record so only the 54th generation of Kong Sihui and their descendants and the first three generations of the Kong family, Confucius, Confucius's son Kong Li and Kong Li's son Kong Ji were venerated in tomb offerings. Late Imperial China's Board of ritual administered government academies, education and civil examinations. They took on special meanings near and in Qufu as special ritual places were chosen as the places to build education institutions and academies. Students could only be educated at one academy, Academy of the Four Clans run in the 17th century by the Kongs out of the five shuyuan (academies) in total run by them. They were foremost centers of ritual, where sacrifices would be carried out and li would be performed for the "first teacher" (Confucius).