Segóbriga was an important Celtic and Roman city, and is today an impressive site located on a hill (cerro Cabeza de Griego) near the present town of Saelices.
It is hypothesised that it was initially a celtiberian castro (fortress) that dominated the basin located north of the city, with the defensive advantage of the Cigüela river which served as a moat.
It is thanks to some 3rd and 2nd century BC texts that we know to call the inhabitants of the area towards the Cuenca mountain chains Olcades, those approaching La Alcarria and the province of Guadalajara, Lusones, and toward Toledo, Carpetani.
Pliny the Elder[8] mentions the exploitation of lapis specularis, a variety of translucent gypsum much appreciated at the time for the manufacture of window glass and an important part of the Segobriga economy.
Pliny the Elder in his Naturalis Historia, in section 3.24, lists the towns belonging to the Caesaraugustan Conventus, among which they appear the Ercavicenses (of the city of Ercavica, neighbors of the Segobrigans).
At the end of the mandate of Vespasian the city was at its highest point, having completed the works of the theater and amphitheater, and being fully integrated socially and economically in the Roman Empire.
Its definitive depopulation had to begin after the Muslim invasion of the Iberian Peninsula, when its bishops and governing elites fled towards the north, looking for the shelter of the Christian kingdoms, as it is known that it happened in the neighboring city of Ercavica (Cañaveruelas, Province of Cuenca).
After the Reconquista, the population of the contours moved to the current town of Saelices, located 3 km further north, next to the fountain that nourished the aqueduct that had supplied the ancient city of Segóbriga.
Forgotten and to its name, the hill that it occupied happened to be denominated "Cabeza del Griego", with a small rural population dependent on the town of Uclés, located to only 10 km, coming to use ashlars extracted of the ruins for the construction of its convent-fortress.