September 13 marks 90 years since one of the darkest days in Ibiza's modern history, a day remembered locally as the “diumenge negre” or “Black Sunday”.

On September 13, 1936, the city of Ibiza was bombed by Italian aircraft supporting Franco's forces. Hours later, as Republican forces prepared to leave the island, a group of militiamen killed a large number of prisoners held in the Castle of Ibiza.

Together, the two episodes turned September 13 into one of the most traumatic dates of Ibiza's Civil War history.

The Bombing of Ibiza

Shortly after midday on September 13, 1936, three Italian aircraft attacked Ibiza.

The bombing targeted the port and areas of La Marina and Dalt Vila. The attack caused deaths among civilians and destroyed or seriously damaged buildings across the city.

The exact number of people killed in the bombing remains disputed.

Historian Fanny Tur, cited in the latest historical review, places the death toll at around 20, while other historical accounts have estimated considerably higher figures. The lack of a single definitive figure is one reason historians continue to distinguish between the documented victims and broader estimates.

One of the most heavily affected locations was the Fonda Cires on what is now Carrer de Castelar, where many people were present when the bombs fell.

A City Under Attack

The bombing caused substantial damage in the historic centre.

Buildings in La Marina were destroyed, and some of the damaged properties remained supported by temporary structures for years afterwards.

The attack also caused fear among the population, with people leaving the city and seeking shelter or staying with relatives in rural areas.

Historical records and photographs preserved in Ibiza's municipal archives provide evidence of the destruction caused that afternoon.

The Events at the Castle

The tragedy continued that night.

As Republican forces prepared to abandon Ibiza, prisoners being held in the Castle were killed by militiamen before the departure.

These killings became known as Els fets del Castell.

The exact death toll has also been the subject of historical discussion.

A list preserved in the Arxiu Històric d'Eivissa i Formentera records 105 people killed in the Castle that day. Earlier historical accounts have cited lower figures, including 93.

The victims came from different backgrounds, including military personnel, priests, farmers, business people, workers and students.

Victims Came From Across the Pitiusas

The prisoners killed in the Castle were not all from Ibiza Town.

Historical records show that victims came from different municipalities on Ibiza as well as from Formentera.

Many were subsequently buried in the Cathedral of Ibiza.

Among those killed were 17 members of the clergy.

The large number of religious figures among the victims has made Els fets del Castell a particularly significant episode in the island's religious and historical memory.

A Day Remembered From Different Perspectives

The events of September 13 have been remembered and interpreted in different ways over the decades.

The bombing was carried out by Italian aircraft supporting the Francoist side, while the killings at the Castle were committed by Republican-aligned militiamen as they prepared to leave the island.

Both events formed part of the violence and political conflict of the Spanish Civil War.

For historians, understanding the day requires considering both episodes rather than treating the “Diumenge Negre” as a single event.

Historical Records Continue to Shed Light

The work of local historians and archives has helped recover information about individual victims and the circumstances surrounding the killings.

Recent research by historian José Luis Mir has also examined what happened after September 13, including another bombing of Ibiza on September 14 as people attempted to recover bodies from the previous day's attack.

His research has contributed further documentation to the historical record of the period.

Stories of Survival

Not everyone imprisoned in the Castle was killed.

Some prisoners managed to escape during the confusion by climbing or jumping from the fortress walls.

Historical accounts describe several men surviving their escape despite suffering injuries.

One escaped prisoner reportedly hid in a cave in Buscastell, while others were sheltered by local residents or remained hidden for days.

These stories form another part of the personal history surrounding Els fets del Castell.

Remembering the 20th-Century History of Ibiza

The 90th anniversary comes as Ibiza continues to examine and preserve its Civil War history.

Archives hold photographs, documents, lists of victims and personal accounts that help establish what happened during those years.

The memory of September 13 is particularly important because the events affected both the physical city and numerous families across the island.

For decades, memories of the Castle killings were more widely discussed than the civilian victims of the bombing, something historians have increasingly sought to address.

A Tragedy With Two Chapters

The events of September 13, 1936 cannot be reduced to a single act of violence.

The day began with an aerial attack that struck the port, La Marina and Dalt Vila and killed civilians.

It ended with the mass killing of prisoners in the Castle.

The two episodes occurred within hours of one another and left a lasting mark on Ibiza's collective memory.

Ibiza Marks 90 Years

Ninety years later, September 13 remains a date of remembrance rather than celebration.

The “diumenge negre” recalls a period when Ibiza became directly caught up in the violence of the Spanish Civil War, with civilians, prisoners and religious figures among those who lost their lives.

The precise number of victims may still vary between historical sources, but the scale of the tragedy is not in doubt.

The surviving archives and the work of historians continue to preserve the names and stories behind the numbers, ensuring that one of the darkest days in Ibiza's history is not forgotten.