Ptolemy's Geography in the context of "Cape Delgado"

The Ptolemy world map is a map of the world known to Greco-Roman societies in the 2nd century. It is based on the description contained in Ptolemy's book Geography, written c. 150. Based on an inscription in several of the earliest surviving manuscripts, it is traditionally credited to Agathodaemon of Alexandria.

Notable features of Ptolemy's map is the first use of longitudinal and latitudinal lines as well as specifying terrestrial locations by celestial observations. The Geography was translated from Greek into Arabic in the 9th century and played a role in the work of al-Khwārizmī before lapsing into obscurity. The idea of a global coordinate system revolutionized European geographical thought, however, and inspired more mathematical treatment of cartography.

Agathodaemon of Alexandria (Ancient Greek: Ἀγαθοδαίμων Ἀλεξανδρεὺς, Agathodaímōn Alexandreùs) was a Greek or Hellenized Egyptian cartographer, presumably from Alexandria, Roman Egypt, during late Antiquity, likely in the 2nd century AD.

Agathodaemon is mentioned in some of the earliest manuscripts of Ptolemy's Geography:

The Caledonians (/ˌkælɪˈdoʊniənz/; Latin: Caledones or Caledonii; Ancient Greek: Καληδῶνες, Kalēdōnes) or the Caledonian Confederacy are believed to be a Brittonic-speaking (Celtic) tribal confederacy in what is now Scotland during the Iron Age and Roman eras. The Greek form of the tribal name gave rise to the name Caledonia for their territory. The Caledonians were considered to be a group of Britons, but later, after the Roman conquest of the southern half of Britain, the northern inhabitants were distinguished as Picts, thought to be a related people who would have also spoken a Brittonic language. The Caledonian Britons were thus enemies of the Roman Empire, which was the state then administering most of Great Britain as the Roman province of Britannia.

The Caledonians, like many Celtic tribes in Britain, were hillfort builders and farmers who defeated and were defeated by the Romans on several occasions. The Romans never fully occupied Caledonia, though several attempts were made. Nearly all of the information available about the Caledonians is based on predominantly Roman sources, which may be biased.

A phantom island is a purported island which has appeared on maps but later found not to exist. They usually originate from the reports of early sailors exploring new regions, and are commonly the result of navigational errors, mistaken observations, unverified misinformation, or deliberate fabrication. Some have remained on maps for centuries before being "un-discovered".

Unlike lost lands, which are claimed (or known) to have once existed but to have been swallowed by the sea or otherwise destroyed, a phantom island is one that is claimed to exist contemporaneously, but later found not to have existed in the first place (or found not to be an island, as with the Island of California).