September 13, 2026 marks 90 years since one of the darkest days in Ibiza’s modern history, when an Italian aerial bombardment of Ibiza Town was followed hours later by the killing of around 93 prisoners inside the Castle of Ibiza.

The date became known locally as the “Diumenge Negre”, or “Black Sunday”, a day that brought two separate episodes of Civil War violence to the island within the space of only a few hours.

On September 13, 1936, three Italian aircraft supporting the forces that had risen against the Spanish Republic bombed Ibiza Town. Later that night, as Republican forces prepared to abandon the island, militiamen killed prisoners being held inside the Castle.

Ninety years later, the events remain among the most traumatic chapters in Ibiza’s 20th-century history.

Ibiza Town Bombed From the Air

On the afternoon of September 13, three Italian aircraft attacked Ibiza Town.

Bombs struck the port and parts of La Marina and Dalt Vila, causing extensive destruction and killing civilians.

Historical accounts differ on the exact number of people who died. Around 40 deaths is one of the figures most frequently cited, while other accounts have placed the toll higher.

The differences reflect the difficulties historians face when reconstructing events from wartime records, contemporary testimony and documentation produced under different political circumstances.

What is not disputed is that the attack caused significant civilian casualties and extensive damage in the heart of the town.

Can Cires Became One of the Symbols of the Bombing

Among the locations devastated was the Fonda de Can Cires on Carrer de Castelar.

The building was destroyed while people were inside, making it one of the locations most closely associated with the civilian casualties of the attack.

Other buildings around La Marina and the port were also hit, while vessels in the harbour were damaged.

Eyewitness accounts describe explosions shaking buildings across the town and news of deaths and destruction spreading quickly through the streets.

Fear Spread Across Ibiza Town

The bombing created panic among residents.

People fled the urban centre, sought shelter or travelled into the countryside to stay with relatives as fears grew that further attacks could follow.

Photographs, written testimonies and documents preserved in Ibiza’s historical collections continue to provide evidence of the destruction caused during those hours.

The physical damage would eventually be repaired, but the events of that day remained deeply embedded in the memories of families across Ibiza.

The Tragedy Continued at the Castle

The violence did not end when the aircraft disappeared.

That night, prisoners being held in the Castle of Ibiza in Dalt Vila were attacked by Republican-aligned militiamen.

Approximately 93 prisoners were killed in what became known as Els fets del Castell.

The killings took place as the Republican position in the Pitiüses was collapsing following the failure of the attempt to retake Mallorca and as forces prepared to leave Ibiza.

Historical accounts have frequently described the massacre as a reprisal following the bombing earlier that day.

Around 93 Prisoners Were Killed

Different figures have appeared over the decades, but approximately 93 deaths is the number most consistently associated with the massacre inside the Castle itself.

Higher figures sometimes found in historical records can refer to a wider number of people killed during the period of Republican control in Ibiza and Formentera, rather than exclusively to those who died in the Castle on September 13.

The prisoners came from a variety of backgrounds, including members of the military, clergy, landowners, workers, businesspeople and other civilians.

Many had been detained because they were considered sympathetic to the military uprising or politically opposed to the Republican forces controlling the island.

Religious Figures Among the Victims

Members of Ibiza and Formentera’s clergy were among those killed.

Historical records identify 18 priests among the victims of the Castle massacre, while additional members of the clergy had been killed elsewhere in the Pitiüses during the preceding weeks.

Their deaths became an important part of the religious memory surrounding the Civil War in Ibiza.

The Diocese of Ibiza continues to commemorate priests killed during the conflict, and their stories remain part of the wider historical record of violence during the summer of 1936.

Some Prisoners Managed to Escape

Not everyone held inside the Castle died.

Accounts from the period describe prisoners escaping during the confusion, including men who climbed or jumped from parts of the fortress and fled despite suffering injuries.

Some reportedly remained hidden for days or received assistance from residents.

These survival stories provide another perspective on a night largely remembered through the scale of the killings.

Two Episodes of Violence on the Same Day

Understanding the Diumenge Negre means recognising that September 13 contained two distinct acts of violence.

The afternoon bombing was carried out by Italian aircraft supporting the Francoist forces.

The Castle massacre later that night was carried out by militiamen aligned with the Republican side.

The victims included civilians killed from the air and prisoners killed while in detention.

Both episodes were part of the wider violence unleashed by the Spanish Civil War, which had begun less than two months earlier following the military uprising of July 1936.

Ibiza Had Become Part of a Much Wider War

Ibiza and Formentera had fallen under Republican control in August 1936 following the expedition led by Captain Alberto Bayo.

The Republican attempt to take Mallorca ultimately failed, dramatically altering the military situation across the Balearic Islands.

By September, the Republican position in the Pitiüses was becoming increasingly difficult to sustain.

The events of September 13 occurred during those final days of Republican control. Forces aligned with the military uprising would subsequently take control of Ibiza and Formentera, after which another period of repression followed against people associated with the Republican side.

The island therefore experienced violence and political persecution affecting families on different sides of the conflict.

Historical Memory Has Changed Over Time

How September 13 has been remembered has also evolved.

For decades, public remembrance focused heavily on those killed in the Castle, while victims of the bombing and people later killed during Francoist repression received less public recognition.

More recent historical research and democratic-memory initiatives have sought to document victims from across the conflict and build a fuller account of what occurred in Ibiza and Formentera.

Archives, photographs, burial records, personal testimonies and historical investigations continue to contribute new information.

A Day With Two Chapters

The Diumenge Negre cannot be reduced to a single incident.

It began with aircraft appearing over Ibiza Town and bombs falling around the port, La Marina and Dalt Vila.

It ended with around 93 prisoners losing their lives inside the Castle.

Between them were families searching for relatives, residents fleeing damaged streets and an island facing the rapidly changing front lines of the Spanish Civil War.

The events occurred only hours apart, leaving September 13 permanently marked in Ibiza’s collective memory.

Ibiza Remembers 90 Years Later

Ninety years after September 13, 1936, the Diumenge Negre remains a day for remembrance and historical reflection.

Some details, particularly casualty figures from the bombing, continue to differ between historical sources. But there is no dispute about the extraordinary scale of the violence Ibiza experienced that day.

The surviving photographs, documents, testimonies and names of the dead transform the events from statistics into individual human stories.

Remembering both the people killed in the aerial attack and those killed inside the Castle helps preserve a fuller account of one of the darkest days in Ibiza’s modern history.