The only building still intact è the aforementioned palatine chapel dedicated to St. Anne, which is located on the eastern edge of the fortification. The building, which è has been described as «an expression of regional Gothic […] all archaisms and Byzantine and Norman reminiscences» has a hall-like layout, oriented canonically along the west-east axis, with a small apse emerging, while externally it appears as a compact volume covered by a gabled roof and punctuated by pilasters at the cornerstones and the center of the side walls.
The only surviving building intact is the palatine chapel dedicated to St. Anne, which is located on the eastern edge of the fortification.
In the austere elevation, which once gave onto the courtyard connected to the castle courtyard, there is an ogival portal surmounted by a small rose window, while another round-arched entrance is located on the northern side.
The interior of the chapel è is divided into two square bays, covered by cross vaults, defined by ribs with a circular section and separated by an archway with a straight profile; the ribs at the four corners rest on hanging corbels, while in the center they converge on three small columns, the base of which è is supported by corbels figured with animal heads, plant and geometric motifs.
The apse, on which a slender single-lancet window opens, è bordered at the corners by pairs of columns arranged in different planes, the outer ones twisted and the inner ones smooth, both supporting capitals with bulbs and leaves, while the basin è defined by a double archway, whose ferrules include a circular outline. The two small niches, with trefoil arches placed at the sides of the apse, re-propose in contracted form the prosthesis and diaconic proper to the Byzantine rite, whose influence on medieval Sicilian architecture was è perpetrated for a long time; two other large recesses with ogival termination, which originally must have contained arcosolium noble tombs, are carved in the thickness of the side walls.
The south wall is the one with the same shape as the apse.
In the southern wall, off-center from the niche below, è placed a rectangular opening surrounded by squared ashlars (currently blind), larger in size than the other windows; because of its position è it is possible to assume that it was in connection with the rooms of the castle, now found only in the traces on the ground, and that it served as a women’s gallery to attend sacred functions.
The dating and commissioning of the chapel can in the first instance be derived from a marble cartouche, today arranged inside it, in which it reads: «anno incarnati (onis) verbi M° CCC° XI° none indicioni(s) regnante domino nostro rege Friderico III excellentissimo rege Sicilie Regni eius anno XVI nos Franciscus comes vigintimilii yscle maioris Giracii dominus utriusqe Petralie incepimus hanc eclesiam beate gloriose virginis (in Christi) nomine edificare». Althoughé this inscription records as the date of the start of the construction of the chapel the year 1311 and traces it back to the willà of Count Francesco I Ventimiglia, it must be assumed that a place of worship already existed within the castle, in fact some documentary evidence confirms an earlier installation: from a deed dated March 8, 1239 (in modern style 1240), we learn that Emperor Frederick II conferred to Nicolò Terciario, cleric of the Palatine ofPalermo, the chaplaincy of the «Cappellam Castri nostri Geracii in Sicilia…».
By that date Geraci, which had belonged to the domain of Alduin of Candida, had been temporarily forfeited by the Curia regia. Moreover, when around the middle of the thirteenth century the castle came to the Ventimiglias, the original chapel must have held the skull of St. Anne, patron saint of the family, which had been donated by the Duke of Lorraine to William, Count of Ventimiglia and Lozano, who came to Sicily around 1242 «and brought with him the sacred Head of the glorious Mother St. Anna, which he then placed in the ancient castle of the city of Geraci…». In the chapel is preserved the canvas of the Nativity of the Virgin, dating from the first half of the 17th century and referable to the sphere of the learned painter Giuseppe Salerno, known by the pseudonym of Zoppo di Gangi.