Perthes, in France, described pieces that were balanced, symmetrical and crafted with a formal purity. Vilanova i Piera published similar works in Spain. This work was continued by Pérez de Barradas and del Prado at the start of the 20th century. As Leroi-Gourhan explained, it is important to ask what was understood of art at the time, considering the psychologies of non-modern humans. Archaeological records documenting rapid progress towards symmetry and balance surprised Leroi-Gourha. He felt that he could recognize beauty in early prehistoric tools made during the Acheulean: Many authors refer only to exceptional pieces. The majority of hand axes tended to symmetry, but lack artistic appeal. Generally, only the most striking pieces are considered, mainly 19th or early 20th century collections. At that time a lack of knowledge regarding prehistoric technology prevented a recognition of human actions in these objects. Other collections were made by aficionados, whose interests were not scientific, so that they collected only objects they considered to be outstanding, abandoning humbler elements that were sometimes necessary to interpret an archaeological site. Exceptions include sites methodically studied by experts where magnificently carved, abundant hand axes caused archaeologists to express admiration for the artists: The discovery in 1998 of an oval hand axe of excellent workmanship in the Sima de los Huesos in the Atapuerca Mountains mixed in with the fossil remains of Homo heidelbergensis reignited this controversy. Given that this is the only lithic remnant from this section of the site (possibly a burial ground), combined with the piece's qualities led it to receive special treatment, it was even baptized Excalibur and it became a star item. However, the symbolic meaning of this example in particular, and hand axes in general, has multiplied in recent years, feeding both scientific and more general debate and literature. Basch offered this counterargument: Paradoxically, within the wide range of Acheulean objects, hand axes are one of the simplest tools. They do not require as much planning as other types of object, generally made from flakes, that are less striking but more sophisticated. Archaeologists have evidence of hand axes that are 1.2 million years old in Melka Kunturé (Ethiopia), but the oldest, from Konso-Gardula, could be 1.9 million years old: Although it is now known that they are the heritage of a number of human species, with Homo ergaster the earliest, up until 1954 no solid evidence indicated who had fabricated