The only other examples of Korean Buddhist sculpture from the 4th or 5th century are some terra cotta fragments from Goguryeo. Some scholars believe that the paucity of extant images from the earliest period of Korean Buddhism is due to the fact that the religion was practiced by a small number of aristocrats and did not become popular with the general population until the 6th century. Another reason for the lack of early images may be because the site of the earliest period of Baekje history is within the city of Seoul, an area so developed that it is difficult to excavate, while Goguryeo archaeological sites are generally off limits to South Korean scholars because they lie mostly in North Korea.