This Palace, residence throughout the centuries of the People's Captain, of the Podestà, then of the Elders, and lastly of the Pontifical Governors, is no less than the very text that can be read of the city's history. From the 13th century, era of the fusion of three medieval buildings and of a patrician tower re-adapted as a bell tower, the building in the course of time has undergone many transformations. In the latter half of the 1400's, a mezzanine was constructed between the first and second floors and the building was lengthened on its southern side. The posterior façade of the Palate, realized in 1520 by the architect and painter Nicola Filotesio, known as Cola dell'Amatrice, follows a typically Mannerist style. After the Christmas Fire of 1535 (an arson by order of the Papal Commissary Giambattista Quieti, set with the aim of uprooting a political rebellion) the Palate was entirely remodelled. Also involved in this restructuring is the internal courtyard, framed by three orders of lodges and realized by the Ascolan architect Camillo Merli. In the superior part of the Entrance; realized in 1549 by master craftsmen from Lombard, rises the monument of Pope Paul III Farnese.

Along the side of the Church of S. Francesco, rises the Merchants' Lodge dating from the 1500's. This columned lodge in a style inspired by Bramante, has its columns resting upon large cubes to give the construction more dynamism according to the rules of Classical architecture. The lodge was erected by the powerful Wool Corporation.
Of particular note: underneath the lodge, a stone tablet of travertine has been fixed to the wall near the lateral entrance. This stone shows the measurements of all of the types of bricks and files (including those of the roof covering) prescribed in 1569 and useful for future intervention purposes.

The Baptistery is one of the most interesting examples of Romanesque architecture in all of Italy. Dating from the early Middle Ages, it was reconstructed in the latter part of the 12th century. Internally one will find the original circular basin used for baptism by immersion. The geometric forms that this building manifests have a clearly symbolical significance: the inferior part follows a squared ground plan, representing the terrestrial sphere; the dome symbolizes the heavenly sphere, that is, the immensity of the macrocosm; the central part, of octagonal form, stands to represent the meaning of Baptism as an intermediary between the earthly and the divine.

The church, begun in 1258 and terminated only in 1549 with the dome's construction, is an example of Gothic architecture. Another monument dedicated to an important Pope, Julius II della Rovere, is present in the lateral portal. The work refers to a reestablishment of the Order following the imprisonment of the noble Ascolan Astolfo Guiderocchi, the "tyrant" mentioned in the stone tablet of the monument.
The principal portal of S. Francesco is one of the most precious examples of art using the local travertine: the arcade is comprised of small columns, each differing in form and interrupted by knots in the inferior zone, and terminating at the level of the overhead frame with a lacework of ornamental stone tracery using floral motifs. The most recent construction of the square is represented by the Caffè Meletti, in Art Deco style, inaugurated in 1907.

Noteworthy aspects of this church are: The façade with its 64 panels that once contained frescoes, the lunette portal from 1306 (with the sculptural group of the Virgin with the titular Saints of the church) and the crypt, dedicated to S. Silvestro, protector against leprosy, which houses a fount using water that comes directly from a spring of water that is considered curative.

The Cathedral rises up from the foundations of a public Roman building. Already utilized as a place of worship in early Christian times, it was entirely reconstructed in the form of a Latin Cross with a single nave in the second half of the 6th century and beginning of the 7th century. Conserved from this phase are the bases of the two frontal towers, the cupola and the crypt where the relics of the Saint are conserved. From 1482, year of the Libertas Ecclesiastica, the Cathedral underwent its most visible transformations with the construction of the two lateral aisles, the new central apse and, in the successive century, the advancement of the façade with the absorbition of the two towers following a design by Cola dell'Amatrice; according to a scheme of a Roman triumphal arch. Other significative interventions have been: at the beginning of the 1700's the re-arrangement of the central part of the crypt for the insertion of a sculptural group of S. Emidio; in 1838 the opening of the Neoclassical Chapel of the Holy Eucharist, where the Polyptych of Crivelli and the Silver altar frontal (latter part of the 1300's) are situated; in the years 1884-94 the decoration realized in frescoes of both the dome and the ceiling of the central nave were painted by Cesare Mariani.