- "Portolano" redirects here. For the nautical chart, see Portolan chart.
It was known as a periplus ("sailing-around" book) in Classical antiquity and a portolano ("port book") to Medieval Italian sailors in the Mediterranean Sea. Portuguese navigators of the 16th century called it a roteiro, the French a routier, from which the English word "rutter" is derived. In Dutch, it was called a leeskarte ("reading chart") and in German a Seebuch ("sea book").
Before the advent of nautical charts in the 14th century, navigation at sea relied on the accumulated knowledge of navigators and pilots. Plotting a course at sea required knowing the direction and distance between point A and point B. Knowledge of where places lay relative to each other was acquired by mariners during their long experience at sea.
The earliest peripluses of classical antiquity were not necessarily written as practical navigational handbooks. Some were more akin to an adventure travelogue, to celebrate a famous voyage. Others were disguised as such, notably the Periplus of Pseudo-Scylax from the 4th century BCE, which described the harbors and landmarks along the north African coast west of the Nile delta. Still others were designed as commercial guides for merchants, such as the Periplus of the Erythraean Sea, written around 100 CE by a Greek merchant in Egypt, as a guide to the market ports of the Red Sea and Indian Ocean.
The re-emergence of maritime commerce in the Mediterranean Sea during the Middle Ages (12th–13th centuries), spearheaded by Italian ports like Amalfi, Pisa, Genoa and Venice, led to the rise of a new set of handbooks, known as portolani ("port books"), designed for the practical use of mariners. These were likely first compiled by professional mariners and pilots, probably as a mnemonic set of notes for their own personal use. These notes were probably passed secretly within their profession ranks, from master to apprentice. Only a few of these Italian handbooks were made public, and even fewer have survived to this day. The most complete surviving portolano is the famous Il compasso da navigare, written c. 1250 and published in Genoa in 1296.
In their sailing instructions, Medieval portolan handbooks distinguished between various types of routes, e.g. per starea (coastal cabotage), per peleggio (open-sea sailing between two points). Portolan handbooks expressed their sailing directions in terms compass rose points and distances. The reliance on the magnetic compass (an instrument that only really began being used for navigation in the 13th century.) distinguishes the Medieval portolano from the earlier Classical periplus.
It is believed that the nautical charts that suddenly emerged in Genoa, Venice, Majorca and other maritime centers after the late 13th century were constructed from the written information contained in contemporary written pilot handbooks, hence the term portolan charts. The wealth of detail contained in portolano handbooks is reflected in the portolan charts, stunningly accurate even by modern standards.
Handbooks often contained a wealth of information beyond sailing directions. For instance, they frequently had detailed physical descriptions of shorelines, harbors, islands, channels, notes about tides, landmarks, reefs, shoals and difficult entries, instructions on how to use navigational instruments to determine position and plot routes, calendars, astronomical tables, mathematical tables and calculation rules (notably the rule of marteloio), lists of customs regulations at different ports, medical recipes, instructions on ship repair, etc. As a result, the nautical chart never fully replaced the handbook, but remained supplementary to it.
Among notable rutters is the Grand Routier, written by the French pilot Pierre Garcie, c. 1483 and published in 1502–03, which focused on the shores of the Bay of Biscay and the English Channel, and its peculiarities. Translated into English as the Rutter of the Sea in 1528, it was reprinted many times, and remained the pre-eminent rutter used by English sailors for decades.
Perhaps the most dramatic rutter was the 1595 Reysgheschrift by Dutch sailor Jan Huygen van Linschoten. Having sailed to the Asia aboard Portuguese ships, Linschoten publicized the sailing directions to the East Indies that had been assiduously kept secret by the Portuguese for nearly a century. The publication of Lischoten's rutter was an explosive sensation, and launched the race by a myriad of Dutch and English companies for the East Indies in its aftermath.
- Periplus of Pseudo-Scylax (4th century BCE, Greek)
- Periplus of the Erythraean Sea (100 CE, Egyptian Greek)
- Liber de existencia riveriarum et Forma Maris Nostri Mediterranei (c. 1160–1200, Pisan) 
- Il compasso da navigare (1296, Genoese)
- Grant Routtier et pilotage de la mer (c. 1483, by Pierre Garcie, French)
- Cornaro Atlas (c. 1489, Venetian)
- Reysgheschrift vande navigatien der Portugaloysers in Orienten (1595, Jan Huygen van Linschoten, Dutch).
- Taylor, (1956: p. 103); Parry (1963: p. 85)
- Aczel (2001)
- Brown (1949: p. 103), Taylor (1956: pp. 111–12). See also Lanman (1987) and Campbell (1987, 2011)
- Edson (2007: 51)
- Waters (1985: p. 241); also Markham (1880: p. 355). The first English edition (1528) of Garcie was entitled The Rutter of the Sea, with the laws of the yle of Auleron and translated by Robert Copeland. Copies of the third edition (1541) contained "A rutter of the northe, compyled by Rychard Proude".
- Koeman (1985), Schmidt (2001: p. 153)
- "Book of the position of the coasts and the form of our sea, the Mediterranean". Uncovered in Patrick Gautier Dalché (1995) Carte marine et portulan au XIIe siècle. Le Liber de existencia rivieriarum et forma maris nostri Mediterranei, Pise, circa 1200 Paris: Boccard.
- Motzo, B.R. (1947) Il compasso da navigare: opera italiana della metà del secolo XIII. Pref. e testo del Codice Hamilton 396, Annali della Facoltà di Lettere e Filosofia della Università di Cagliari, pp. 1–137.
- Breusing, A. (1876) Das Seebuch von Karl Koppmann. Bremen: Kühtmann. online
- Esmeraldo de Situ Orbis, 1892 edition, Lisbon: Imprensa Nacional.online
- Livro de Marinharia: tratado da agulha de marear. Roteiros, sondas, e outros conhecimentos relativos á navegação, first pub. 1903, Lisbon: Libanio da Silva. online
- Originally published separately in 1595, the rutter Reysgheschrift was reprinted in 1596 as the second part of Linschoten's Itinerario (1596). In the 1598 English translation, the rutter was inserted as the Third Book.
- Aczel, A.D. (2001) The Riddle of the Compass: the invention that changed the world. New York: Harcourt.
- Brown, L.A. (1949) The Story of Maps. 1979 edition, New York: Dover.
- Campbell, T. (1987) "Portolan charts from the late thirteenth century to 1500", in J.B. Harley and D. Woodward, editors, The History of Cartography, Vol. 1 – Cartography in Prehistoric, Ancient, and Medieval Europe and the Mediterranean. Chicago: University of Chicago Press, p. 371–63 online (PDF)
- Campbell, T. (2011) "A critical re-examination of early portolan charts with a reassessment of their replication and seaboard function" (online)
- Cotter, C.H. (1983) "A Brief History of Sailing Directions", Journal of Navigation, Vol. 36, p. 249–51.
- Edson, E. (2007) The World Map, 1300–1492: the persistence of tradition and transformation. Baltimore, MD: The Johns Hopkins University Press.
- Koeman, C. (1985) "Jan Huygen van Linschoten", Revista da Universidade de Coimbra, Vol. 32, p. 27–47. offprint
- Lanman, J.T. (1987) On the Origin of Portolan Charts. Chicago: Newberry.
- Markham, A.H., editor, (1880) The Voyages and Works of John Davis, the Navigator, London: Hakluyt. online
- Nordenskiöld, Adolf Erik (1897) Periplus: An Essay on the Early History of Charts and Sailing Directions, tr. Frances A. Bather, Stockholm: Norstedt.
- Parry, J.H. (1963) The Age of Reconnaissance: Discovery, exploration and settlement, 1450 to 1650. 1981 edition, Berkeley: University of California Press.
- Schmidt, B. (2001) Innocence Abroad: the Dutch imagination and the New World, 1570–1670. Cambridge, UK: Cambridge University Press.
- Stevenson, E.L. (1911) Portolan charts; their origin and characteristics: with a descriptive list of those belonging to the Hispanic society of America. New York: Knickerbocker Press. online
- Taylor, E.G.R. (1951) "The Oldest Mediterranean Pilot", Journal of Navigation, Vol. 4 (1), p. 81–85.
- Taylor, E.G.R. (1956) The Haven-Finding Art: A history of navigation from Odysseus to Captain Cook, 1971 ed., London: Hollis and Carter.
- Waters, D.W. (1985) "English navigational books, charts and globes printed down to 1600", Revista da Universidade de Coimbra, Vol. 33, p. 239–57. offprint