Semaphore in the context of "Peace dove"

A number of peace symbols have been used many ways in various cultures and contexts. The dove and olive branch was used symbolically by early Christians and then eventually became a secular peace symbol, popularized by a Dove lithograph by Pablo Picasso after World War II. In the 1950s, the "peace sign", as it is known today (also known as "peace and love"), was designed by Gerald Holtom as the logo for the British Campaign for Nuclear Disarmament (CND), a group at the forefront of the peace movement in the UK, and adopted by anti-war and counterculture activists in the US and elsewhere. The symbol is a superposition of the semaphore signals for the letters "N" and "D", taken to stand for "nuclear disarmament", while simultaneously acting as a reference to Goya's The Third of May 1808 (1814) (aka "Peasant Before the Firing Squad").

The V hand signal and the peace flag also became international peace symbols.

Flag semaphore (from the Ancient Greek σῆμα (sêma) 'sign' and -φέρω (-phero) '-bearer') is a semaphore system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used (with hand-held flags replacing the mechanical arms of shutter semaphores) in the maritime world in the 19th century. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or, using lighted wands instead of flags, at night.

A flag is a piece of fabric (most often rectangular) with distinctive colours and design, often flown from a pole and used for symbolic, signaling, or decorative purposes. The term flag is also used to refer to the graphic design employed on such pieces of fabric. The study of flags is known as "vexillology" from the Latin vexillum, meaning "flag" or "banner".

The first flags were used to aid military coordination on the battlefield, and flags have since evolved into a common tool for basic signaling and identification, especially in environments where communication is challenging (such as maritime environments where semaphore is used). The national flag is a common patriotic symbol of a country, and many national or other flags may be assigned to flag families based off similarities in their structure that demonstrate a shared history, culture, or influence. Flags are also used in messages, advertising, or for other decorative purposes.

In the 9th century, during the Arab–Byzantine wars, the Byzantine Empire used a semaphore system of beacons to transmit messages from the border with the Abbasid Caliphate across Asia Minor to the Byzantine capital, Constantinople.

According to Byzantine sources (Constantine Porphyrogenitus, Theophanes Continuatus and Symeon Magister), the line of beacons began with the fortress of Loulon, on the northern exit of the Cilician Gates, and continued with Mt. Argaios (identified mostly with Keçikalesı on Hasan Dağı, but also with Erciyes Dağı near Caesarea), Mt. Samos or Isamos (unidentified, probably north of Lake Tatta), the fortress of Aigilon (unidentified, probably south of Dorylaion), Mt. Mamas (unidentified, Constantine Porphyrogenitus has Mysian Olympus instead), Mt. Kyrizos (somewhere between Lake Ascania and the Gulf of Kios, possibly Katerlı Dağı according to W. M. Ramsay), Mt. Mokilos above Pylae on the southern shore of the Gulf of Nicomedia (identified by Ramsay with Samanlı Dağı), Mt. Saint Auxentius (modern Kayış Dağı) south-east of Chalcedon (modern Kadıköy) and the lighthouse (Pharos) of the Great Palace in Constantinople. This main line was complemented by secondary branches that transmitted the messages to other locations, as well as along the frontier itself.