The site of the ancient hippodrome course in Olympia, where the emperor Nero competed for Olympian laurels, has been discovered. The hippodrome was discovered in Olympia by a research team that included Professor Norbert Müller (a sports historian from Mainz), Dr Christian Wacker (a sports archaeologist from Cologne) and PD Dr Reinhard Senff (chief excavator of the German Archaeological Institute - DAI.

"This discovery is an archaeological sensation," commented Norbert Müller of the Johannes Gutenberg University Mainz. The research project extended over several weeks before being completed in the middle of May 2008.

Prior to this, the hippodrome had only been known from written sources. Archaeologists had failed to locate its actual site. This is surprising, as German archaeologists have been continuously excavating the site of where the ancient olympiad was held since 1875; this research has become a tradition and innumerable archaeologists, historians, and sports historians from all over the world have been involved in trying to solve this secret for over a hundred years.

Pausanias, a travel writer of the ancient world, described this course for horse races, its starting mechanisms, turning points and altars in much detail in the 2nd century AD: "If you climb over the stand of the stadion along the side where the hellanodikai are seated, you reach a terrain, where the horse races and the starting mechanism for the horses are located. The starting mechanism has the form of the prow of a ship, with the tip pointing to the race-track. Along the side where the prow touches the column of Agnaptos, it is broad. At the farthest tip of the prow there is placed a bronze dolphin on a pole (11) Both sides of the starting mechanism are more than 400 feet long and there are starting gates incorporated in them.

These starting gates are assigned by lot to the competitors in the horse races. A cable is stretched out as starting barrier before the chariots or the ridden horses. An altar of unbaked brick, plastered on the outside, is constructed every Olympiad in the centre of the prow. (12) On the altar there is an eagle with outstretched wings. The race director operates a device inside the altar. When it is put into motion, the eagle flies up, so that it is visible for the spectators, and the dolphin falls to the ground. (13) The first cables to fall down are those on both sides of the column of Agnaptos and the horses in these positions leave first.

They now draw level with those who have drawn the lot for the second place and the starting ropes are lowered here; this procedure continues until all the horses are level in a row at the tip of the prow. At this point the drivers can begin to demonstrate their skills and the speed of their horses. (14) It was Kleoitas who invented the starting device and he was so proud of his invention that his statue in Athens bears the following inscription: "The first inventor of the starting mechanism for horses at Olympia made me: Kleoitas, son of Aristokles." It is said that a certain Aristeides modified this invention. (15) "The racecourse has one side longer than the other, and on the longer side, which is an earthen bank, there can be found, at the passage through the bank, Taraxippos, the Horse-Frightener." (Pausanias VI 20.10-15)

Another - previously unheeded - written source from the 11th century AD goes so far as to state the size and dimensions of the enclosure: "The olympiad has a course for horse races that [has a length of] 8 stadia. Each of the long sides is 3 stadia and 1 plethron long, while the width to the starting gates measures 1 stadion and 4 plethra, [a total of] 4800 feet. Near the Taraxippos, behind which - so it is said - there is concealed an ancient hero, the horses run around a turning post; the finishing point of the race, however, is the pillar of Hippodameia. Among the horses, those in the foal category run a distance of 6 stadia, while those in the adult category run 12 stadia; chariots with a pair of foals travel three times around the circuit and those with adult horses eight times; chariots with four foals complete a total of eight circuits, while those with four adult horses complete 12 circuits." (Tabula Heroniana II, Fol. 27f.)

To date, it had been assumed that nothing of the hippodrome had survived, as the area described by Pausanias to the east of the sanctuary of Olympia has been flooded by the Alfeios River since ancient times and has become covered with silt. In modern plans and descriptions it is usually stated quite simply that "nothing remains of the hippodrome due to flooding in medieval times".

This served as an additional incentive for the German researchers: Using modern geophysical methods, they systematically searched the area for the first time. The experts Armin Grubert (Mainz) and Christian Hübner (Freiburg), who specialize in the use of geomagnetic and georadar techniques, were able to map soil disturbances such as water courses, ditches, and walls. Conspicuous, rectilinear structures were indeed discovered along a stretch of almost 1200 meters. The researchers believe this to be the racecourse, which ran parallel to the stadium. Structural remains identified as the temple of Demeter that is known to have been sited near the hippodrome were discovered in the northern part of the area investigated in the spring of 2007.

Of particular interest is the fact that at the halfway point of the northern access to the starting-gates - where Pausanias describes entering the hippodrome - there is a circular arrangement with a diameter of about 10 meters, clearly marked in the ancient soil layer, which could be the remains of the sacred structure described here by the ancient writer. The actual starting-gates, with boxes for up to 24 teams of horses, are most probably located under a gigantic pile of earth excavated by the archaeologists investigating the temple area since 1875.

The investigation of the area east of the sanctuary of Olympia, only made possible by the research funds provided by the Institute of Sports Science of the University of Mainz and the International Riding Association, has produced the first concrete indications of the location of the racecourse and its geographical dimensions.. Ten students were on hand to assist the sports historian Professor Norbert Müller, who is an authority on Olympia. "The DAI, with its branch in Athens, has done sports history a great service through its contribution," said Müller. "The project could become a new attraction for the sports world, similar to the excavation of the ancient Olympic stadium 50 years ago."

The area east of the sanctuary of Olympia had not been the subject of archaeological investigation before, although the ancient written sources show that this must have been the site of the largest construction, in area terms, built to host competitions. According to Pausanias, the hippodrome lay south of the now researched and reconstructed stadium, and must now be several meters below the current level. It is only here, between the adjoining hills on the other side of the road to Arcadia in the north and the bed of the Alfeios River in the south (which has since been straightened) that the topology is suitable for the accommodation of a racecourse with a length of more than one kilometer.

Nevertheless, the geological and geographical conditions are not favorable. On the one hand, intensive agricultural use has produced stark changes to the historical geography, and, on the other hand, the course of the Alfeios River, which once meandered through the plain, has changed several times over the centuries. The landscape in this area has changed so much that it is nearly impossible to reconstruct its appearance in ancient times. It is known today that the level of the river in medieval times was about 9 meters higher than in ancient times, but that about 7 meters of the deposited material has since been eroded and carried away by the river. This means that the ancient remains to the east of the sanctuary lie about 2 meters below the current level.

The racecourse described in such detail by Pausanias (Book VI 20.10-15) was located at this level. According to this author, the teams lined up in the shape of a prow of a ship in starting-gates in front of a hall; the starting signal was a brass eagle that was raised and lowered by means of a hoisting mechanism, while a dolphin figure moved in front of the drivers. There was space for spectators along a wall on the southern side and along the adjoining hills to the north, but it seems that there were no stone stands similar to those of the great circuses in Rome or Carthage.

Various reconstructions have been based on Pausanias' description, with the racecourse usually assumed to be twice as wide as the starting-gates. However, it was only after a hand-written medieval document from the 11th century was correctly reinterpreted by J. Ebert in 1989 that the actual appearance and dimensions of the hippodrome became apparent. The complex had a length of 1052 meters and a width of 64 meters, not including the earth walls built for the spectators. The starting-gates stretched the full width of the racecourse.

Modern geomagnetic methods were used by a team of German scientists in April/May 2008 to explore the accessible terrain at the level described above. Two different physics-based techniques were used. Geomagnetic mapping of archaeological structures involves the accurate, high-resolution recording of the tiny magnetic anomalies in the earth's magnetic field that these cause. Such anomalies are usually caused by the presence of foundations, large stone objects or burnt layers. This technique was used in combination with georadar, a ground penetrating form of radar. In this electromagnetic technique, short impulses that each last only a few nanoseconds are radiated into the ground. These are reflected by the margins of different layers and by objects. A combination of the two methods can be used to detect anomalies and even to determine at what depth they are located in the ground. This makes it possible to determine within which layer (modern, medieval, ancient) the identified anomalies are probably located.

An area of 10.5 hectares was finecombed with geomagnetic mapping techniques, while georadar was used to investigate an area of 3.6 hectares. It was not always possible to penetrate the thick layers of fine sand, while the remains of decades of agriculture in the form of fences, channels and concrete structures also made results difficult to interpret.

Nevertheless, some significant finds were made. It appears that there was never extensive construction on the site. The innumerable channels extending to the northern perimeter of the area once defined the edges of terraces or water drainage conduits. The Alfeios River would have repeatedly flooded the entire area up to the foot of the hills. As the ancient level is approximately 2 meters below the current level, however, any remains will have been protected to some extent. This means that the parallel anomalies (ditches, walls, earthworks) identified along a length of almost 200 meters must represent the remains of the ancient hippodrome.

The hippodrome was thus sited parallel to the stadium and ended where there is a distinctive bend in the modern road at its eastern turning point. Approximately half-way along the northern access route to the starting-gates - where Pausanias entered the hippodrome - a circular stone formation with a diameter of about 10 metres was found in a layer dating from ancient times. Some remains that were most probably once buildings located on a terrace have been discovered near the road on the northern side of the hippodrome. As remains of a temple of Demeter have been discovered by Greek archaeologists in the immediate vicinity underneath the modern road, it now seems likely that this was the location described by Pausanias.

Hence, without any need for excavation, modern geomagnetic techniques have given us the first clear indications of the site of the hippodrome east of the sanctuary of Olympia. This means that archaeological and sports-historical research has come a little closer to solving one of the last great mysteries of Olympia.