Having resolved to document the life of Julius Caesar and devote a part of his work to the Gallic Wars, in 1862 the Emperor Napoleon III charged a topography commission(56) to identify Uxellodunum. The commission first placed the oppidum at La Pistoule, Luzech, in a loop of the Lot.
This site would have been definitively adopted if Jean-Baptiste Cessac, native of Gourdon, and an inhabitant of Souillac, had not protested against the official decision by sending several letters to Napoleon III and publishing several brochures (1862-1865).
To confirm his opinion, he carried out excavations at the fountain of Loulié from 27 May 1865. The discovery of a number of objects - iron catapult bolts and arrow heads, burnt stones and earth, as well as many fragments of charcoal - allowed Cessac to obtain funding to continue the work from the topography commission.
Eventually on the 19th June 1865, at a depth of 5m, Cessac found a man-made tunnel. This discovery was sensational given that Caesar's Gallic Wars documents that Caesar had ordered tunnels to be constructed below the spring in order to capture the water and thus drive the Gauls to defeat. Napoleon III immediately sprang to Cessac's aid and despatched two officers, Colonel Stoffel and Captain de Reffye, with a platoon of engineers, who continued the search. These excavations were intended by Napoleon III to put a stop to the quarrels.