First written of by the Greek explorer Pytheas of Massalia (modern-day Marseille, France) in about 320 BC, it was often described by later writers as an island north of the British Isles.

Pytheas mentioned going to Thule in his now lost work, On The Ocean Τὰ περὶ τοῦ Ὠκεανοῦ (ta peri tou Okeanou).

Polybius in his work The Histories (c. 140 BC), Book XXXIV, cites Pytheas as one "who has led many people into error by saying that he traversed the whole of Britain on foot, giving the island a circumference of forty thousand stadia, and telling us also about Thule, those regions in which there was no longer any proper land nor sea nor air, but a sort of mixture of all three of the consistency of a jellyfish in which one can neither walk nor sail, holding everything together, so to speak.

"[10] The first century BC Greek astronomer Geminus of Rhodes claimed that the name Thule went back to an archaic word for the polar night phenomenon – "the place where the sun goes to rest".

[14] Strabo, in his Geographica (c. AD 30),[15] mentions Thule in describing Eratosthenes' calculation of "the breadth of the inhabited world" and notes that Pytheas says it "is a six days' sail north of Britain, and is near the frozen sea".

But from the other writers I learn nothing on the subject – neither that there exists a certain island by the name of Thule, nor whether the northern regions are inhabitable up to the point where the summer tropic becomes the Arctic Circle.

In AD 77, Pliny the Elder published his Natural History in which he also cites Pytheas' claim (in Book II, Chapter 75) that Thule is a six-day sail north of Britain.

The third-century Latin grammarian Gaius Julius Solinus wrote in his Polyhistor that "Thyle, which was distant from Orkney by a voyage of five days and nights, was fruitful and abundant in the lasting yield of its crops".

Solinus (d. AD 400) in his Polyhistor, repeated these descriptions, noting that the people of Thule had a fertile land where they grew a good production of crop and fruits.

It is believed that Procopius is really talking about a part of Scandinavia, since several tribes are easily identified, including the Geats (Gautoi) in present-day Sweden and the Sami people (Scrithiphini).

There is another set of small islands, nearly all separated by narrow stretches of water; in these for nearly a hundred years hermits sailing from our country, Ireland, have lived.

But just as they were always deserted from the beginning of the world, so now because of the Northman pirates they are emptied of anchorites, and filled with countless sheep and very many diverse kinds of sea-birds.

I have never found these islands mentioned in the authorities".A map of the world voyage done by Sir Francis Drake in 1577-1580 shows Thule (Tile/Tule) as what is likely modern Iceland near Greenland.

[35] The British surveyor Charles Vallancey (1731–1812) was one of many antiquarians to argue that Ireland was Thule, as he does in his book An essay on the antiquity of the Irish language.

The island group became a British overseas territory of the United Kingdom, albeit also claimed by Argentina (in Spanish Islas Tule del Sur).

It was formerly the terminus of the known-explorable southeastern (upstream) end of the passage called "Main Cave", before discoveries made in 1908 by Ed Bishop and Max Kaemper showed an area accessible beyond it, now the location of the Violet City Entrance.

In March 2018, following a naming competition, the Kuiper belt object 486958 Arrokoth, a fly-by target of the NASA probe New Horizons, was nicknamed "Ultima Thule".

[citation needed] A work of prose fiction in Greek by Antonius Diogenes entitled The Wonders Beyond Thule appeared c. AD 150 or earlier.

(Gerald N. Sandy, in the introduction to his translation of Photius' ninth century summary of the work,[46] notes that this Thule most closely matches Iceland.)

The "known world' of the Europeans came to be viewed as bounded in the east by India and in the west by Thule, as expressed in the Consolation of Philosophy (III, 203 = metrus V, v. 7) by Boethius.

"[47] By the Late Middle Ages, scholars were linking Iceland and/or Greenland to the name Thule and/or places reported by the Irish mariner Saint Brendan (in the 6th century) and other distant or mythical locations, such as Hy Brasil and Cockaigne.

These scholars included works by Dicuil (see above), the Anglo-Saxon monk the Venerable Bede in De ratione temporum, the Landnámabók,[citation needed] by the anonymous Historia Norwegie,[citation needed] and by the German cleric Adam of Bremen in his Deeds of Bishops of the Hamburg Church, where they cite both ancient writers' use of Thule as well as new knowledge since the end of antiquity.

Eustathius of Thessalonica, in his twelfth-century commentary on the Iliad, wrote that the inhabitants of Thule were at war with a tribe whose members dwarf-like, only 20 fingers in height.

Edgar Allan Poe's poem "Dream-Land" (1844) begins with the following stanza: By a route obscure and lonely, Haunted by ill angels only, Where an Eidolon, named Night, On a black throne reigns upright.

This affords the only thoroughly scientific system; and nowhere but in its legitimate conclusions can thought find suitable resting-place, the heart complete satisfaction, and life a perfect basis.

Materialism, thorough, consistent, and fearless, not the timid, reserved, and half-hearted kind, is the hope of the world.Kelly Miller, addressing the Hampton Alumni Association in 1899, explained that "Civilization may be defined as the sum total of those influences and agencies that make for knowledge and virtue.

[54] Ultima Thule is mentioned in The Name of the Rose by Umberto Eco in reference to an illuminated manuscript that the narrator/character Adso sees when he explores the library labyrinth alone at the end of the third day.

[56] He uses the phrase to connect the study of Latin in his younger years to his more recent efforts to read the Icelandic poet Snorri Sturluson.

[57] Some followers of ariosophy in early 20th-century Germany hypothesized a historical Thule, or Hyperborea, as the ancient origin of the "Aryan race" (a term which they believed had been used by the hypothetical Proto-Indo-European people).

Much of this interest in Thule was initially due to rumours surrounding the Oera Linda Book, claimed to have been found by Cornelis over de Linden in the 19th century.