With Muslim Kingdoms and Maritime Republics dominating trade to their east, the Kingdoms of Portugal and Castile explore the Atlantic Ocean and the coasts of Africa.


Iberian Peninsula

The Iberian Peninsula is located in the south-western corner of Europe. It is mostly water locked by the Mediterranean Sea in the east and the Atlantic Ocean in the west.

Kingdoms of Iberia

Iberia is home to the Muslim kingdom of Granada and the Christian Kingdoms of Aragon, Castile, Portugal, and Navarre. The peninsula becomes known as Spain after the Roman name of Hispania.

Atlantic Ocean

The 106,460,000 KM² Atlantic Ocean is the second largest ocean on Earth. It covers about 20 percent of the Earth’s surface. Medieval Europeans call it the Dark Sea.

Trade Winds

Portuguese navigators begin to better understand wind patterns and ocean circulation. They sail counter-intuitively in the wrong direction to catch winds blowing in a specific direction.

The Atlantic Ocean is named after the Greek Sea of Atlantis. English Cartographers called it the Great Western Ocean.

Exhausted Mines

Easily accessible ore deposits such as gold and silver are nearly depleted in Europe. Mines can’t go any deeper without flooding. European kingdoms are running low on ores and enter a recession.

Spice Trade

There is high demand for spices such as cinnamon, ginger, pepper, clove, and nutmeg. The trade of spices, as well as sugar from sugarcane, is highly lucrative in Europe and Asia.

Trade Monopolies

The Islamic Ottomans control major overland trade routes, while the Maritime Republics of Venice and Genoa have a monopoly at sea. They dominate the trade of precious metals and spices.

Iberian Exploration

The ocean-side Kingdoms of Castile and Portugal increasingly look for resources in the Atlantic Ocean. They also hope to find sea routes to bypass the Maritime and Muslim trade monopolies.

The Canary Islands

There are eight major islands off the northwestern coast of Africa. It also has many small islands and islets. The archipelago is home to stone-age natives known as the Gaunches. 

Colonization of the Canaries

1402 CE: King Henry III of Castile grants Jean de Béthencourt the right to colonize the Canaries. The French Explorer conquers the island of Lanzarote and captures the Guanches to sell as slaves.

Kingdom of the Canary Islands

1404 CE: Jean de Béthencourt receives the title King of the Canary Islands but recognizes Henry as his overlord. The French explorer becomes the first ruler of the Kingdom of the Canary Islands.

Aristocratic Conquest

1405 CE: Jean de Béthencourt and Gadifer de la Salle invade additional islands in the Canaries. Meeting heavy resistance, the nobles engage in a long-war with the native Guanches.

The Canaries means Island of the Dogs and likely refers to the large dogs that resided on the islands. It is not, as popularly believed, named after Canary birds.

The Colonization of the Canaries marks the earliest beginning of the Spanish Empire and Colonialism. However, the earliest conquests were mostly done by nobles and not directly by kingdoms.

African Slave Trade

Warfare and slavery has been common in many regions of Africa for hundreds of years. Conquering tribes and pirate raiders often sell their prisoners as slaves to African slave markets.

Barbary Pirates

Islamic pirates raid the Iberian coastline and capture inhabitants to sell in the African slave trade. Entire villages are depopulated as people are captured or move inland for safety.

Port-City of Ceuta

The city of Ceuta on the north-east coast of Africa belongs to the Islamic Marinid Sultanate. It is a popular port-city and a major base of operations for Barbary Pirates.

Conquest of Ceuta

1415 CE: King John of Portugal organizes a naval fleet and decisively conquers Ceuta. However, trade shifts to the Muslim port-city of Tangier and Ceuta begins to drain the Portuguese treasury.


Prince Henry

Lord Henrique, a son of King John of Portugal, desires to explore the western coast of Africa and the Atlantic Ocean. He wants to bypass Muslim and Maritime trade dominance and find new resources.

Team of Sagres

1419 CE: Henry assembles experts in navigation, sailing, ship design, cartography, astronomy, and mathematics in Sagres. The Atlantic ocean port-city is located on the south-western tip of Portugal.

Porto Santo

Portuguese ships are driven off-course by a storm. They find shelter on an island which they name the Holy Harbor. Henry dispatches an expedition to claim the island for Portugal.


The Porto Santo expedition discovers a larger island and due to its dense forest they call it the Island of Wood. Settlers plant sugarcane to manufacture the rare commodity known as sweet salt.

Sugar was called Sweet Salt by Medieval and Early Modern Europeans.

Governor Henry

1420 CE: The Templars were banished in France over 100 years ago, but the Iberian branch reformed as the Portuguese Order of Christ. Henry the Navigator is now appointed governor of the order.

Calendar Change

The Kingdom of Portugal phases out the Spanish Era calendar in favor of the Anno Domini system. They add 38 years to their calendar so it matches up with the widely used A.D. system.

Cape Bojador

Several ships are lost near rugged cape in North-West Africa. Sailors dare not sail further south due to a sudden change of wind, rough rocky coastline, and rumors of sea monsters.

Bojador Failures

1422-1434 CE: With the help of Italian bankers, Henry funds 14 expeditions to find a route around Cape Bojador. However, over a period of 12 years, the Templar flagged ships fail to cross the cape.

Cape Bojador is just north of the Equator. The Cape is called Abu Khatar in Arabic, which means Father of Danger. In case someone may be wondering, it does not have sea monsters.

The Azores

1433 CE: The Portuguese discover an archipelago with nine volcanic islands about 1400 km west of Portugal. It is soon settled by the Portuguese who plant crops for export and sustenance.

The Passing of Bojador

1434 CE: Prince Henry sponsors his shield-bearer Gil Eanes to find a way to pass Cape Bojador. After an initial failure, he manages to pass the cape using trade winds and safely return home.

Exploration of West Africa

1435 CE: Eanes returns to explore the coast of West Africa. He finds a bay with red fish and calls it the Cove of Reds. Other Portuguese navigators soon use the passable route to explore further south.

Navigation Secrets

Prince Henry’s team carefully records winds, tides, currents, and coastlines and creates increasingly accurate sea charts. However, the information becomes very secretive.

Portuguese navigators develop the technique for navigating Trade Winds. They call it Volta do Mar, which means Turn of the Sea.

The First Black Slaves

1430s: Slaves in Iberia are mostly acquired from battles with Islamic kingdoms in North Africa. However, Portuguese navigators now deliver their first cargo of Black African slaves to Portugal.

Anti-Slavery Decrees

1434-1435 CE: Slave raiders capture Christian natives in the Canaries. Due to complaints from clergy on the islands, Pope Eugene gives two public decrees that forbids enslaving Guanche converts.

Disaster of Tangier

1437 CE: Henry lays siege to the port-city of Tangier, but his fleet is defeated by a Marinid Sultanate counter-attack. The prince is forced to sign a treaty that gives up the port-city of Ceuta.

King Afonso of Portugal

1438 CE: King Edward of Portugal dies of the plague and is succeeded by his son Afonso V. Henry the Navigator is the brother of Edward and uncle of Afonso V.

The earliest European slave traders argued that the black slaves are from the Islamic Kingdoms of North Africa. 

Nuno Tristao

1440s: Nuno Tristao is a Portuguese knight and explorer in the household of Prince Henry. The prince has Tristao explore further down the coastline of West Africa using a prototype Caravel ship.

First European Slave Market

1441-1444 CE: Traders establish a network with African slavers and begin to important thousands of black slaves from Africa. The first European slave market is opened in Lagos, Portugal.

Sailing to Guinea

Nuno Tristao is the first sail to pass the Sahara desert and reach sub-Saharan Africa. He calls the forested region Terra dos Guinea, which means Land of the Blacks.

Slave Raids

1446 CE: Nuno Tristao raids local fishing villages and captures African people for slavery. However, during his fourth voyage, he is ambushed by natives and killed along with most of his crew.

The Caravel

Portugal perfects the smaller, faster, and more maneuverable Caravel ship. It has a greater ability to sail further into the ocean, but also sail closer to coastlines and in shallow rivers.

The Carrack

Portugal and Castile develop larger sailing ships. These newly designed Carracks allow for increasingly greater storage and ocean stability. They become popular for long-distance trade.

Senegal River

Portuguese sailors discover the mouth of the 1,086 km long Senegal River in West Africa. They trade goods for gold and slaves with small African states along the river.

Sugar Plantations

Sugar plantations are established in the Canaries and on Madeira and are maintained by slaves. It competes with Venice Sugar. Although still expensive, sugar becomes more accessible in Europe.

Carrack may be descended from the Arabic Qaraqir, which means Merchant Ship.

Battle of Los Alporchones

The Emirate of Granada invades the client Kingdom of Murcia while the Castilians are engaged in civil war. However, the Kingdom of Castile unites and dispatches an army which devastates the Granada army.

The Ottoman Empire

The Ottoman Turks from Northwestern Anatolia have been expanding their territory for the past 100 years. Their Islamic empire now spreads throughout the Balkans, North Africa, and the Middle East.

Fall of Constantinople

1453 CE: The Ottoman Empire conquers Constantinople after a 53-day siege. It brings an end to the Byzantine Empire and further cuts off Western Europe from trade in the East.

Slavery Decrees

In response to Ottoman conquests and expansion, Pope Nicholas V issues decrees that authorizes King Afonso V of Portugal to conquer and subjugate Muslims and Pagans to perpetual servitude.

Pope Nicholas’s decrees legitimizes slavery under Catholic beliefs and pushes the growing slave trade to new heights. However, future popes seek to refine, limit, or forbid slavery.

Discovery of Cape Verde

1455-1456 CE: Prince Henry sponsors Venetian navigator Alvise Cadamosto to explore West Africa. Blown off course by a storm, he discovers an archipelago off the western-most coast of Africa.

Exploration of Santiago

1460 CE: Prince Henry sponsors Genoese navigator Antonio de Noli to further explore Cape Verde. He visits the largest island in Cape Verde. It is named Santiago, which means Saint James.

Death of Henry

66-year-old Prince Henry dies and is buried in a royal tomb in the Batalha Monastery. It becomes tradition for sailors to say a prayer in the monastery’s chapel before departing for a voyage.

Ribeira Grande Settlement

1462 CE: Antonio de Noli settles in Santiago around a river named Ribeira Grande, which means Big Stream. King Afonso V of Portugal soon promotes Noli as the governor of Cape Verde.

Ribeira Grande is known today as Cidate Velha, which means Old City. It was the first European colonial settlement in the tropics.

Guinea Exploration

1470-1471 CE: Portuguese navigators João de Santarém and Pedro Escobar explore the Gulf of Guinea and southern coastlines of Ghana. They discover the uninhabited islands of São Tomé and Príncipe.

The Gold of Elmina

Santarém and Escobar discover a gold industry run by the Fante People in Ghana and begin a lucrative trade in gold with their chieftain. The region becomes known as Elmina, which means The Mine.

Phantom Island of Bacalao

1472 CE: Portuguese navigator João Vaz Corte-Real and German privateer Didrik Pining explore west of Iceland. They may have reached an island that becomes known as the New Land of the Codfish.

Central Africa Exploration

1473-1474 CE: Portuguese navigator Lopes Gonçalves explores the Gulf of Guinea and the southern coastlines of Nigeria. He pushes southward and soon reaches the western coastline of Central Africa.

Lopes Gonçalves was the first European to sail across the Equator.

João Vaz Corte-Real and Didrik Pining may have found Newfoundland and discovered North America 20 years before Columbus. However, there is much debate over the contradictory, anecdotal, and late historical details.

Portugal and Castile engaged in the War of the Castilian Succession between 1475-1479 CE. It is covered in the Spanish Inquisition page.


Controversial Royal Marriage

Prince Ferdinand II of Aragon eloped with second cousin Princess Isabella of Castile. However, the marriage of cousins is prohibited and it is not considered entirely legal by many nobles.

Fake Papal Decree

Pope Paul II refuses to officially recognize the marriage of Ferdinand and Isabella. In response, a papal decree authorizing the marriage is faked with aid from clergy in the Spanish church.

Princess Joanna

Princess Joanna is the only child of King Henry IV of Castile and Joan of Portugal. The 10-year-old Joanna, half-niece of Isabella, is pledged in marriage to her Uncle King Afonso V of Portugal.

Queen Isabella

1474 CE: King Henry IV dies and his half-sister Isabella, who was named as his official successor, becomes queen of Castile. However, some nobles believe daughter Joanna to be the rightful heir.

The marriage of Ferdinand and Isabella brought a dynastic union between the Spanish Kingdoms of Aragon and Castile. It is the beginning of what will become the Kingdom of Spain.

Invasion of Castile

1475 CE: King Afonso marries Joanna and proclaims himself ruler of Castile. He marches 14,000 soldiers and 5,600 cavalry into Castile and secures the town of Toro, which is loyal to Joanna.

Military Allies

Prince Ferdinand supports his wife Isabella with an army from Aragon. However, Portugal is also joined by Castilian nobles that support Joanna as the rightful heir to the Kingdom of Castile.

Siege of Burgos

The Castle of Burgos in Castile is controlled by supporters of Joanna. Ferdinand’s army lays siege to the fortress, while Isabella’s forces block Portugal’s army from reaching the border stronghold.

Battle of Toro

1476 CE: Castile and Portugal forces engage in a major battle near the town of Toro. The battle ends in a stalemate with heavy casualties on both sides. Much of Afonso’s army retreats to Portugal.

Royal Recognition

1476-1477 CE: Isabella claims victory at Toro. With Castile appearing to be strongly under her control, many nobles abandon their allegiance to Joanna and recognize Isabella as the rightful heir.

French Support

King Afonso of Portugal sails to France and requests aid against their mutual rival Castile. King Louis XI, having just recently ended the Hundred Years’ War, only sends a small force.

Invasion of Elmina

1478 CE: Castile sends thirty-five ships with the plan of invading Elmina in Africa. The goal is to capture Portugal’s monopoly of gold in Guinea and redirect remaining forces away from Castile.

Battle of Guinea

Portugal learns of the Elmina attack and swiftly prepares a fleet of eleven ships. The Castilian fleet, anchored and trading with the natives, are ambushed and decisively defeated in Guinea.

King Ferdinand II

1479 CE: King John II dies and Ferdinand II officially succeeds as ruler of Aragon. The Spanish kingdoms Aragon and Castile are increasingly unified under the royal dynastic union.

The Treaty of Alcáçovas

King Ferdinand II and Queen Isabella sign a peace treaty with Portugal. It brings an end to the four-year war between Castile and Portugal. It is a land victory for Castile and a sea victory for Portugal.

Royal Rights

The Treaty of Alcáçovas recognizes Isabella as the rightful queen of Castile in exchange for a large sum of gold. It also requires that Castilian nobles that fought for Joanna to be pardoned.

Atlantic Ocean Division

The Treaty of Alcáçovas recognizes Castile as the legal owner of the Canary Islands. It recognizes Portugal’s territory, both discovered and undiscovered, south of the Canaries and in Africa. 

The Treaty of Alcáçovas is the earlist known legal document to include a law for “future discoveries”.


King John II 

1476-1482 CE: King Afonso V mostly retires to a monastery and leaves rulership to his son John II. Afonso dies a few years later and John II becomes sole ruler of Portugal.

Elmina Castle

With trade flourishing in Elmina, King John dispatches ten caravels, 600 soldiers, and 100 carpenters to build a fortress and protect their trade in Africa. The fort is named Saint George of the Mine Castle.

The Coasts

The trade of gold, slavery, pepper, and ivory in West Africa brings a major boost to Portugal’s economy. Regions named after their resources: The Gold, the Slave, Petter, and the Ivory Coasts.

Prosperous Santiago

The Island of Santiago in Cape Verde becomes a popular stop-over for traders and explorers traveling between Europe and Africa. Ribeira Grande gradually grows into the second richest city of Portugal.

Elmina Castle is the first permanent European settlement in Africa south of the Sahara Desert.  

Columbus in Portugal

Christopher Columbus is an Italian navigator from the city-state of Genoa. However, he is married to Portuguese noblewoman Filipa Moniz Perestrelo and lives in Lisbon, Portugal.

Charts & Maps

Columbus inherits sea charts from his deceased father-in-law who was a captain for Henry the Navigator. Columbus also works with his brother as a mapmaker with his brother Bartholomew.

Conquest of Gran Canaria

 1483 CE: The Kingdom of Castile conquers the Canary island of Gran Canaria from the native Gaunches. The large island has extensive forests and becomes an important port-island.

African Trade 

Columbus engages in trade for Portugal along the coast of Africa and reaches the trading post of Elmina. However, he returns home to find that his wife has passed away.

Congo River Discovery

King John II sponsors Portuguese navigator Diogo Cão to resupply at Elmina Castle and explore further down the coast of Africa. He discovers the mouth of the Congo and explores the river a short distance.

Kingdom of Kongo

Diogo Cão discovers the river Kingdom of Kongo and interacts with King Nzinga a Nkuwu. The large kingdom has several provinces and is a heavy influence on surrounding kingdoms.

South Africa

1484 CE: Diogo Cão sails further down the coast of West Africa and reaches the tip of Southern Africa. The region is named Angola, which derived from the royal title of the local chieftains.

Portugal Visit

Diogo Cao returns to Portugal with King Nzinga a Nkuwu and other Congo nobles. The African natives visit Portugal for over a year before returning home with the Portuguese navigator.

The Congo is the second largest river in Africa, the second largest river in the world by water discharge, and the deepest river on earth.

Trade Monopolies Continued

With the Ottoman conquest of Constantinople a few decades earlier, the Islamic empire continues to monopolize trade with their Maritime Republic allies of Venice and Genoa.

Deadly Journeys

It would be a major benefit for Portugal to bypass the Mediterranean and trade directly with Asia. However, thousands of sailors and many ships are lost attempting to reach Asia by sailing around Africa.

Columbus’ Idea

Using older sources, Columbus estimates the earth’s circumference to be about 25,255 KM. He thinks it is possible to sail across the Atlantic Ocean and establish direct trade with lucrative Eastern Asia.

Rejected Proposal

1484 CE: Columbus first proposes his ocean voyage to King John II of Portugal. However, royal advisors argue that his calculations are incorrect and reject his proposal.


Portugal and Castile establish a presence in the Atlantic.