There is a human at a plough drawn by two oxen, holding what might be a branch or an ox-goading crop made of a number of strips of hide.[3] Some have been painted red to make them more visible for tourists; a practice which has drawn criticism for removing the authenticity and original state of the drawings.The first professional recordings were made in 1792 by Carl Gustaf Gottfried Hilfeling, who was sent by nobleman Pehr Tham to draw the carvings.A number of excavations and recordings took place over the course of the early 19th century, primarily led by Carl Georg Brunius and Axel Emmanuel Holmberg, who published research and debated at length the most likely era of their creation.Strong arguments for the now accepted era were not made until the late 19th century, when Oscar Montelius and Viktor Rydberg presented evidence linking the drawings to the Bronze Age.