Despite its stern and fortified appearance, the Alcázar of Segovia has also been a place of daily life. Many princes, nobles, and infants have grown up within its halls, and their presence has helped soften the palace's appearance, making the castle a home for many.

Its history begins in the 12th or early 13th century when the royal family of Castile had quarters in the Alcázar, known as the "major palace". In the Homage tower, the treasure of the Crown of Castile was stored, from which funds were secured to finance Christopher Columbus's first voyage. In 1437, the books of the royal administration were moved to the Alcázar, establishing one of the first royal archives of Castile and laying one of the foundations for the current General Archive of Simancas. Additionally, the Alcázar housed the royal armory, which served as the basis for the one now exhibited in the Royal Armoury of Madrid.

The Alcázar has been the stage for crucial events in Spain's history, such as meetings of the Cortes of Castile, held there on multiple occasions; the signing of the Concord of Segovia, which laid the groundwork for the formation of the Spanish nation, took place there; Isabel the Catholic, one of the most significant and influential women in history, left the Alcázar to proclaim herself queen of Castile. It was also the site of the last meeting between Christopher Columbus and King Ferdinand the Catholic before the explorer's death. The marriage of Philip II to Anna of Austria strengthened the alliance between the House of Habsburg and the Hispanic Monarchy. As the headquarters of the royal college of artillery, in the 18th century, the first military flight for military purposes was carried out, marking the beginning of military aviation, and the chemist Joseph Proust, a professor at the Royal College, formulated the Law of Definite Proportions, a fundamental advance in modern chemistry.

The Alcázar of Segovia, like many fortifications in Spain, started off as a Roman castrum, but apart from the foundations, little of the original structure remains. The alcázar was built by the Berber Almoravid dynasty. Almoravid art and architecture is scarcely talked about in scholarship in part because so little of the physical work has survived in Spain. Furthermore, the Almoravid dynasty was short-lived and therefore much of the art and architecture of that period was subsequently destroyed or converted by their successors.

The first reference to this castle was in 1120, around 32 years after the city of Segovia was conquered by the Christians (during the Reconquista when King Alfonso VI reconquered lands to the south of the Duero river, down to Toledo and beyond). In 1258, during the reign of King Alfonso X of Castile (r. 1252–1284), an intense thunderstorm caused a fire that destroyed several rooms, leading to centuries-long reconstruction during the reigns of various kings.

The Alcázar of Segovia was one of the favorite royal residences starting in the 13th century that in turn, led to secular patronage to the city of Segovia. It was during this period that most of the current building was constructed by the House of Trastámara. In 1258, parts of the Alcázar had to be rebuilt by King Alfonso X after a cave-in and the Hall of Kings was built to house Parliament soon after. However, the single largest contributor to the continuing construction of the Alcázar was King John II of Castile who built the "New Tower" (John II tower as it is known today).

In 1474, the Alcázar played a major role in the rise of Queen Isabella I. On 12 December news of King Henry IV's death in Madrid reached Segovia and Isabella immediately took refuge within the walls of the Alcázar where she received the support of Andres Cabrera and Segovia's council. She was enthroned the next day as Queen of Castile and León. The next major renovation at the Alcázar was conducted by King Philip II after his marriage to Anna of Austria.[citation needed] He added the sharp slate spires to reflect the castles of central Europe.[citation needed] In 1587, architect Francisco de Mora completed the main garden and the School of Honor areas of the castle.

The restoration of the Royal College of Artillery was among the many reforms conducted under the reign of King Charles III of Spain (r. 1759–1788). He appointed Count Félix Gazzola as the director of the artillery corps, who made the executive decision to install the academy in the Segovian fortress in the Alcázar. At its opening in 1764, the military college stood as a symbol of the city's new age of progress in political and military education. On 6 March 1862, another fire occurred at the castle, destroying the sumptuous ceilings of the private rooms that were reserved exclusively for the nobility. As demonstrated in the engravings by José María Avrial and Flores in 1839, the structures were restored to their previous appearances.

The exterior of the castle has a Herrerian style courtyard, moat, drawbridge, and keep. The interior rooms include a chapel and several noble rooms (cuartos del Trono, de la Galera, de las Piñas, de los Reyes and others) that can be visited today.[4] A triumphal arch, located on the corner of the south-east part of the palace, just beyond the moat, was likely ornamented with heraldic devices and served as a grand entrance to the alcázar. However, today it no longer survives. It was changed during the Habsburg period sometime during the 16th century. The castle sits on a hill overlooking the city, with four towers, and several halls that are constructed with barrel vaults and twin windows. In the interior, the halls and rooms were decorated with great luxury and beauty by Mudéjar painters and artists.

The tower of King John II of Castile (r. 1406–1454) was built during the first half of the 15th century. The style is notably recognized as Spanish Gothic architecture, with influences from Islamic art, such as a horseshoe arch found during renovations in the souther-side of the tower. The tower culminates in a large panoramic terrace with two pointed arches of varying heights built into the walls of the eastern and western portions of the tower. On the east-side of the tower, a large, doubled Gothic window that reached to the floor and facing the city of Segovia was built so that the king's entire body could be seen by others as he stood, framed by the window.

Hall of the Old Palace

Its construction corresponds to the reign of Alfonso VIII of Castile.[citation needed] In it the twinned windows that gave light to the palace are conserved, since the wall in which they were was the exterior wall of the old palace. The Mudéjar-style socles located between the windows come from a 13th-century house in the nearby Las Canonjías district. The decoration was completed with a set of German-style armor from the 15th century.

Hall of the Fireplace

Corresponds to the ordination of the fortress in the time of Philip II of Spain. The furniture is from the 16th century. On the walls you can see a portrait of Philip II and another of Philip III, a 16th century Flemish tapestry with the subject of Our Lady's betrothal and a curious representation where you can contemplate the appearance of the Alcázar before the reform of the roofs and where you can also see the Former Cathedral of Segovia that was located in the current square of the Alcázar.

Throne Room (Salón del Solio)

The walls of the Throne Room mostly consist of portraits of various kings, which are part of the collection of kings commissioned by Queen Isabella II of Spain. Both portraits are signed by their respective artists: the portrait of Isabella I of Castile is signed by Madrazo, while the portrait of Ferdinand II of Aragon is signed by Montañés.

In addition, there is a depiction of the ruler himself "en siella" (seated). This image corresponds to the fact that extant written documents from the fourteenth century actually referred to the throne room as the "rey en siella" (king sitting on the throne; enthroned king). Often these rooms were used for different types of political ceremonies, including the receiving of foreign embassies, banquets, musical performances, and literary events. The rooms could be decorated with different types of objects, like tableware and textiles (including tapestries) that allowed for the space to be transformed to suit the particular event.

Hall of the Galley (Sala de la Galera)

The mother of John II, Queen Catherine of Lancaster (r. 1390–1406) commissioned the construction of the Hall of the Galley in 1412. The name of the room derives from the coffered ceiling that was shaped like an inverted ship hull. The frieze is made of Mudéjar plaster with a double inscription: the upper one includes a prayer related to the Eucharist and the lower one offers information about the work displayed in the hall.

There are two stained glass windows in the Hall of the Gallery. One of these windows portrays Henry III of Castile (r. 1390–1406) and his family. The second window portrays King Henry II of Castile (r. 1366–1367) and scenes of the death of Peter I and John II. A painting by Muñoz de Pablos hangs on a wall in the gallery depicting the coronation of the Isabella I of Castile as Queen of Castile and of León in the church of San Miguel of Segovia.

Hall of las Piñas (Sala de las Piñas)

The inspiration for the name of this room comes from the decorative motifs in the Artesonado ceiling that features many pineapple-like motifs. The stained glass window portrays King Alfonso VII (r. 1126–1157) with his daughter, Queen Berengaria of Castile (r. 1217).

Hall of the Kings (Sala de los Reyes)

King Alfonso X (r. 1252–1284) commissioned the construction of the Hall of the Kings. The space has ornamental ceilings and the upper portions of the four walls are decorated with a five-layer cloth. The design and layout of the Hall of the Kings borrowed iconography from the Palace of Alhambra. In the 1400s, King Henry IV of Castile (r. 1454–1474) played a large role in the final design of the Hall of the Kings. Historical and literary references are evident in the decoration, including the storied medieval Castilian knight, El Cid.

King Henry IV's decision to incorporate a gallery that depicted various rulers of Castile and León, in seated positions, into the hall's decoration was designed to demonstrate the political legitimacy of those in power during 15th century Spain. Similar imagery can be found in the King's Hall (Sala de los Reyes) (also sometimes identified as the Hall of Justice) at the Alhambra, where an image of ten seated rulers located in the ceiling vault are believed by some scholars to represent different emirs from the Nasrid dynasty. Other scholars, however, have argued that due to the presence of small coats of arms below the figures and at the two ends of the image, the scene likely represents the ruler, in this case, Muhammad V of Granada (r. 1354–1359), accompanied by a group of wise men, various teachers and literary figures, is a meeting known as a maŷlis. Whoever is illustrated in the imagery in the Alcázar of Segovia's Hall of Kings, the message concerns the representation of political power, dominance, and legitimacy.

Philip II of Spain (r. 1580–1598) commissioned Hernando de Ávila to design one of the statues that represented the kings of Asturias, León and Castile. One of the paintings in the room is a portrait of King Philip II of Spain and the others are portraits of two of his wives, Elisabeth of Valois (r. 1559–1568) and Anna of Austria (r. 1570–1580).

Chapel (Capilla)

The chapel at the Alcázar of Segovia houses Adoration of the Magi (c. 1600) by Italian painter, architect, and sculpture Bartolomeo Carducci. Due to its historical significance and architectural accomplishments, the castle hosted numerous events. One of the most famous events at the Alcázar was the wedding of Philip II of Spain with his niece, Anna of Austria in 1570, which took place in the castle's chapel.

Weapons or Armory Room

The Alcázar has housed the armory of the House of Trastámara since old times, and was the precedent of the collections of weapons that finally met in the Royal Armoury of Madrid. Museum of the Royal College of Artillery (Museo del Real Colegio de Artillería)

The Royal College of Artillery was divided into two parts: the academy and as a meeting place for the military and cadets in training. To attend the school, applicants were exclusively chosen from the noble estate or related to army captains and artillery corps. The allure of the school consisted of not only its scientific and military accomplishments, but in its integration of teachings of Christian ideals.