Raphael and Giulio Romano. It was conceived in a contemporary Renaissance style or "Roman" style with an innovative design reflecting the architectural ideals of this period. The construction of a monumental Italian-influenced palace in the heart of the Nasrid-built Alhambra symbolized Charles V's imperial status and the triumph of Christianity over Islam achieved by his grandparents (the Catholic Monarchs). It consists of a massive square structure of stone which encloses a perfectly circular courtyard. The exterior facades are divided into two horizontal zones of decoration, with rustication below and pilasters alternating with other embellishments above. The two main entrance portals, on the western and southern sides, have designs resembling triumphal arches with engaged columns. The pedestals of these columns are carved with reliefs depicting allegorical scenes such as the Victories destroying armaments, representing the emperor's imposition of a universal peace. The upper façade of the southern entrance portal features a Serlian window. Among the other details of the palace façades are a series of bronze rings or knockers which are strictly ornamental, with more Hispanic symbolic imagery such as lion and eagle heads. Pedro Machuca had intended to create plazas with colonnades on the east and west sides of the building to serve as a grand new approach to the Alhambra palaces, but these were never executed. Construction of the palace began in 1527. After Machuca's death in 1550 it was continued by his son Luis, who finished the facades and built the internal courtyard. Work was halted for 15 years when the 1568 Morisco Rebellion began. Work was still unfinished when Philip IV visited in 1628 and the project was finally abandoned in 1637, leaving the structure without a roof. It was finally completed after 1923, when Leopoldo Torres Balbás began its restoration. Today, the building houses the Alhambra Museum, which holds objects and artefacts relating to the Alhambra's history, as well as the Fine Arts Museum of Granada, which houses a collection of paintings from Granada dating from the 16th to 20th centuries. Other Nasrid palaces Three other major Nasrid-era palaces once existed but were largely destroyed over the centuries. The excavated remains of the Palacio del Partal Alto ('Upper Partal Palace'), also known as the Palacio del Conde del Tendilla ('Palace of the Count of Tendilla'), are incorporated today into the Partal Gardens. The palace dates from the time of Muhammad II, with later renovations and modifications,