The city was founded early in the Bronze Age and was later occupied during the Iron Age by the Celtic people of the Vacceos who called it Ocalam.[1]

After the Roman victory over the Lusitanian hero Viriathus the settlement was named by the Romans Occelum Durii or Ocellodurum (literally, "Eye of the Duero"). During Roman rule it was in the hands of the Vaccaei, and was incorporated into the Roman province of Hispania Tarraconensis. It was on the road from Emerita (modern Mérida) to Asturica Augusta (modern Astorga). (Ant. Itin. pp. 434, 439).

Two coins from the reign of the Visigothic king Sisebuto, show that it was known at the time as "Semure".

Following the campaigns of Musa ibn Nusayr in the 710s in the context of the Umayyad conquest of the Iberian Peninsula, the town was conquered and a Berber garrison was left in the there, but following the Arab-Berber strifes, the territory was reportedly seized by Alfonso I of Asturias.[2] Not much attention was paid however to the place in the chronicles from this period, as Asturian human resources at the time were mostly targeted at the Cantabrian coast and little is known about the inhabitants of the Duero Valley.[2]

According to the chronicle of Al-Andalus by Isa ibn Ahmad al-Razi [es], Alfonso III of Asturias determined the Christian repopulation of the place in 280 AH (893–894 AD) (although the dates of 881, 899 and 910 AD have been also reported).[2] A diocese and a bishop were established in the town in the early 10th century.[3] Mozarab builders came from Toledo.[4] The city became one of the most thriving Christian cities in Iberia in the early 10th century, possibly even passing León.[4]

Zamora became the target of Ibn al-Qitt, who unsuccessfully tried to invade the city in 901 with help from Nafzāwa [es] Berbers.[5] It was also attacked several times during the Caliphal era, and Almanzor eventually seized the city in 966.[6] The place returned to Christian control during the reign of Alfonso V of León.[7]

Since the early 11th century, with the repopulation works by Raymond of Burgundy,[7] the place saw planned repopulating efforts.[8] A new perimeter of city walls was also erected in the 11th century.[9] The population intramuros included the nobles and regal officers, the clergy, Frank settlers from Gascogne, Poitou and Provence who had installed in the city during the time of Raymond of Burgundy,[10] settlers of Asturian, Leonese and Galician origin, as well as some Mozarabs.[11] Zamora was granted a fuero in 1208.[12]

The most notable historic episode in Zamora was the assassination outside the city walls of the king Sancho II of Castile in 1072. Some decades before, king Ferdinand I of León had divided his kingdoms between his three sons. To his daughter, Doña Urraca, he had bequeathed the "well fortified city of Zamora" (or "la bien cercada" in Spanish). All three sons warred among themselves, till the ultimate winner, Sancho, was left victorious. Zamora, under his sister who was allied with Leonese nobles, resisted. Sancho II of Castile, assisted by El Cid, laid siege to Zamora. King Sancho II was murdered by a duplicitous noble of Zamora, Bellido Dolfos, who tricked the king into a private meeting. After the death of Sancho, Castile reverted to his deposed brother Alfonso VI of León. The event was commemorated by the Portillo de la Traición (Treason Gate).

In the late middle ages, Zamora was one of the 17 cities (18 after the inclusion of Granada) that enjoyed a vote at the Cortes of Castile, actually speaking on behalf of all of Galicia since the early 15th century (Galicia did not have any city with representation until the 17th century).[13]

Zamora was also the scene of fierce fighting in the 15th century, during the conflict between the supporters of Isabella the Catholic and Juana la Beltraneja. The Spanish proverb, No se ganó Zamora en una hora, literally, Zamora wasn't won in an hour, is a reference to these battles. It is the Spanish equivalent of the English proverb "Rome wasn't built in a day."

During the 12th century, the city was extraordinarily important for its strategic position in the wars between the Kingdom of León and the Almoravids and Almohads. As a result, the city preserves many churches and buildings from that time. In the 1140s and 1150s it was ruled by Prince Ponce Giraldo de Cabrera, who has a street named after him in the city today.

Henry IV granted Zamora the epithet of "most noble and most loyal city".

 

View of the city of Zamora circa 1570, drawn by Anton van den Wyngaerde.

The city leaned towards support to the Revolt of the Comuneros in the northern hemisphere Fall of 1520.[14] By September 1520, the corregidor appointed by the Crown was ousted and replaced by an alcalde designated by the community (a revolutionary development at the time).[15] However, the hopes of the rebels across the Crown of Castile were handed a crushing blow at the Battle of Villalar on 23 April 1521.[16]

In the Early Modern Period, the city lost its political and economic relevance and suffered emigration, especially to South America (where many other cities called Zamora were founded).

According to the Godoy Census, the city had a population of 10,171 in 1797.[17]

During the Spanish Civil War (1936–1939), Zamora was from the start of the military rebellion a nationalist held city. The savagery of the repression against leftists and liberals is captured in Ramón Sender Barayón's 'A Death in Zamora', which tells of the extrajudicial murder of his mother, Amparo Barayon, the wife of the famous novelist Ramon Sender.