This archeological site is located 7 km northwest of Llerena, on a large area of over 330 ha, in a sector where the three municipal districts of Casas de la Reina, Llerena and Higuera meet. The site corresponds to a modern _trifinium_, although the main nucleus of the structures is in the municipal district of Casas de la Reina. The archeological surveys carried out could not detect any traces of use of the land after Roman times. This peneplain, with gentle relief and sweeping panoramic views, constitutes an extension of the last northern foothills of the Sierra Morena mountain range. This area benefits from permanent water supply points, extensive meadows, pasture areas and a residual holm oak forest. In addition, the abundant surface stone constitutes a practical and inexhaustible construction material, which has turned it into an island surrounded by farmland. Literary sources (Apian, _Iberia_ 67-71), point out the key role played by this region in _Baeturia_ during the Lusitanian Wars. Moreover, it is important to highlight the relative closeness of _Arsa_ and _Regina_, two of the six _oppida_ _non_ _ignobilia_ of the _Baeturia_ _Turdulorum_ quoted by Pliny ( _Nat._ _Hist._ III, 3, 14). (translation by Laura González Fernández)

Research (2003-2005) Surface surveys exposed a number of coordinated elements, extraordinarily well- adapted to the layout of nature: a) two trapezoidal walled areas, a large one and a small one; b) a series of fifteen circular redoubts or small forts in a line of three by three; c) a series of eight small redoubts for further strengthening strategic locations of the complex; d) stone walls _(titula)_ forming a line of parallel obstacles to block the way; e) outbuildings used to shelter and protect the animals travelling with the army and f) a presumably preliminary or earlier military facility. This complex of structures may have met the objective of an overall strategic plan. The “El Pedrosillo” military complex allowed the Romans both, defense against enemies and launching raids into enemy territory simultaneously, as this crucial position ensured close surveillance and direct control of a strategic communication hub. Therefore, this place is more than a simple military camp. It constitutes a unique example of castramentation as well as strategy, in one of the most conflict-ridden territories during the conquest of Hispania. (translation by Laura González Fernández)

During the autumn of 2006 eight sondages of different extension were conducted in both walled areas and their surroundings. The main area (C2) was built in _emplecton_. Its walls, 1/1,20 m high and 1,8/2,50 m wide, enclose a 9,90-ha flattened terraced surface. There is a smaller enclosure (C2a), presenting also a flattened terraced surface, to the southeast of the main walled area. The aim of the first sondages was to identify the technique used to build the walls and determine the existence of possible ditches. Sondage 1 in C2a enclosure revealed the existence of a destroyed large circular construction. Its dimension and characteristics seem to correspond to those of a building (H1), possibly a of the “tumulus” kind, dating to the late Neolitic era or Bronze era. Iron pegs for tents geometrically arranged were found on the Roman level in both, enclosure C2 and C2a. They are similar to those found in the camps of _Numantia_ (mid-second century BC). During cleanup and systematic survey activities numerous stone projectiles, coins and remains of weapons were recovered, all of them characteristic of Roman military settlements. (translation by Laura González Fernández)

During the autumn of 2008, a magnetic and georeferenced intensive survey was carried out with the objective of determining the use of the site in ancient times. Several objects were recovered: lead projectiles _(glandes)_ with no inscription, Hispano-Punic and Roman Republican coins dating to late third century BC, arrowheads, _pilum_ tips, tent pegs to tighten the guy ropes, etc. All these objects fully testify to Roman military presence in this site during the Republican period. It is worth emphasizing that this military complex does not seem to have been subject to siege on the part of Hispanic indigenous communities. (translation by Laura González Fernández)