The Spanish phrase "no hay moros en la costa," meaning there are no Moors on the coast, began centuries ago as a literal all-clear signal on the shores of eastern Spain, not as the figure of speech it is today.

Lookouts stationed in watchtowers along the coastline used the phrase to tell nearby residents that no enemy ships were approaching and that the coast was free of danger, according to the report.

Origins in pirate raids
The need for that vigilance came from repeated attacks by Barbary pirates from North Africa, who raided Mediterranean coastal towns for more than two centuries, looting and stealing as they went, the report said.

The threat did not end when the Reconquista concluded in 1492. Fear of new invasions or pirate attacks persisted, prompting authorities to reinforce the entire coastline with a network of watchtowers meant to warn of approaching strangers.

The cry of "hay moros en la costa," meaning there are Moors on the coast, served as the alarm, while its negation signaled that everything was in order.

From fear of pirates to everyday language
Over time the expression lost its military and literal meaning and became a common saying. Today, when someone says there are no Moors on the coast, they mean there is no danger in sight, that the situation is safe, or that no trouble is expected, the report said. It is used to convey that everything is calm or that someone can act without fear of being caught.

Journalist Adrián Pignatelli wrote in an article for Infobae that the phrase's origin is curious.

According to the report, the word "moro" comes from the Latin "maurus," meaning dark, and was the term used for the Muslims who invaded the Iberian Peninsula in the year 711. After their expulsion, the danger continued with the pirate raids, and it was in that context that the phrase took root in popular speech.
A saying that outlived its origin
Today the expression is so widely used that few people know the history of fear and alertness behind what seems like an innocuous statement of calm, the report noted. It has survived for centuries, transforming from a maritime safety warning into a universal saying for describing the absence of problems.

