What was the Kingdom of Portugal?

Iberian Peninsula

The Kingdom of Portugal was a political state in the west of the Iberian Peninsula (Europe) between the years 1139 and 1910 AD. It became important mainly because the Portuguese were the first to sail to India by sea, surrounding the southern tip of Africa and discovering a new trading route. They were looking for spices (apart from conquering lands, spreading Christianity, etc.). See 'Comercial reasons'.

This glog, created by us, introduces the most important things about Portuguese explorations.

Reasons for the explorations

Religious reasons

  • The Portuguese wanted to spread christianity.

Comercial reasons

  • They needed to find new trade routes to the spices land (in India) because the Turks (Muslims) had conquered the Byzantine Empire and had taken the control of the route of the spices (which
    The route of silk (also used for spices) by land
    was called the trade route of silk). Spices were very important in the Middle and Modern Ages because they were only way of preserving food, specially meat.
  • Cosequently, the europeans had to pay heavy taxes to get to the spices.
  • There was a political interest against the Crown of Castile and a militar interest against the Muslims.
  • During the 15th century, the Portuguese suffered a financial crisis, reason for the eagernes of getting gold and slaves from Sudan.

Intelectual reasons

  • The Renaissance men were very adventurous and they wanted to know more and more every day.
  • Henry the Navigator (a Portuguese nobleman who promoted the first expeditions to Africa) had good economic means at his disposal, and stablished in Sagres (cape of San Vicente) a center of nautical, geographical and cosmographic studies with Majorcan geographers and Italian sailors. The work in Sagres was promoted specially by the scientific curiosity.

Technical reasons

  • Navigational instruments that helped the orientation during navigation were created:
    • The compass: it has two needles which are always pointing to the north and to the south. It is used to locate your position on the Earth. This way, ships could move farther from the coast.


    • The rudder: it is an articulated piece of wood or metal used to steer a ship.


    • The astrolabe: it is an object used to locate your position on Earth thanks to the orientation of the stars.

Operation of the astrolabe

  • Ships were improved, like the caravel, which could transport more people and cargo and travel faster and more distances

  • Portulan charts were created. They were a type of map which showed the coastline, the obstacles at sea and the best natural ports.

Other reasons

  • The portuguese army was expert because it had been fighting during the Reconquest of the Iberian Peninsula and the Kingdom of Portugal was on an excellent geographical position for exploring.
  • The portuguese thought that there was a Chistian Kingdom in the south of Africa, governed by a king called Prestor John. They wanted to become his allies and conquer together the Islamic Empire.

The first years of explorations

Between 1385 and 1433 Juan de Avis (Juan I or John I) governed in Portugal. He promoted politics of expansion, inluding maritime, starting the intervention in Africa, leaded by his son Henry the Navigator´s initiative. He opened the Portuguese expansion with the conquest of Ceuta (1415).
The taking of Ceuta meant the possession of a good place to fight against Muslim pirates, and was also an entrance to the Mediterranean Sea and the north of Africa, apart fom being an important point for channeling the Portuguese trade with Morocco and a base for avoidig Castilian expansion in this country and the Atlantic Ocean.

Prince Henry the Navigator

Prince Henry the Navigator (1394-1460) was the son of the Portuguese king Juan I (or John I), although he never got the reign, because he had two elder brothers, Edward (later Edward I) and Pedro. He is very important because he supported a lot of expeditions to Africa along his life, although he never sailed in his explorations. I you want to know more about him, please click on the following link:
Henry the Navigator

The treaty of Alcaçobas

Treaty of Alçacobas
The rivalry between the Crown of Castile and the kingdom of Portugal for the possession of the Canary Islands and the monopoly of trade in the coast of Guinea obliged the Portuguese and Castilian monarchs to stablish an agreement, signed by: Isabel I of Castile, Ferdinand II of Aragon, Alfonso V of Portugal and Joao, prince of Portugal.

The treaty of Alcaçobas (1479) gave the Portuguese free rain to continue their explorations along the African coast and the rights in some african kingdoms, while the Castilians received the Canary Islands. It also prohibited Castilians sailing among the Portuguese possesions without their permission.

The treaty of Alcaçobas established Castilian and Portuguese control in the Atlantic Ocean and settled, for a while, a period of hostility. It is true that Castilians won the Canary Islands but, while the Portughuese where making their explorations, the kingdom of Castile decided to find new routes to Asia and the spices without entering places under their control (Africa and part of the Atlantic Ocean).

The treaty of Tordesillas

external image Treaty.jpg
external image Tordesillas.gif
The treaty of Tordesillas was a later agreement between the Crown of Castile and the Kingdom of Portugal. The discovery of America by Christopher Columbus obliged them to create this new treaty, in which the imaginary dividing line of the treaty of Alcaçobas was moved west, 370 miles away from Cape Verde Islands.

The territories in the east of the line belonged to the Kingdom of Portugal.
The territories in the west of the line belonged to the Crown of Castile.

However, when Ferdinand Magellan and Juan Sebastian Elcano demonstrated the world was round, a second line had to be created to divide the Earth into two parts.

More explorations lead by the Kingdom of Portugal

Travelling was not easy in the Middle and the beginning of the Modern Ages. Technology was not as advanced as nowadays. It was even tought that the world was flat. A lot of people died during the explorations. If you want to konw more about the difficulties during the expeditions or more expeditions the Portuguese did, click on the link below:
Other explorations to Africa and difficulties

Bartolomeu Diaz was a Portuguese explorer in the end of the 15th century and the beginning of the 16th. He is famous because he got to the Cape of Good Hope (the most southern point in the west of Africa). Although he did not get to India, his discovery meant that a sea route around Africa to this country was possible. To know more about him, click here:
Bartolomeu Diaz's exploration

Vasco da Gama was a Portuguese explorer in the end of the 15th century and the beginning of the 16th. He is famous because he was the first to get to India by surrounding Africa. To know morw about him, click here:
Vasco da Gama's exploration

The Portuguese did not only explore Africa and India; they also got to America. They had rights over the current country of Brazil. The first Portuguese explorer who got there was Pedro Alvares Cabral. To know more about the foundation and colonization of Brazil, click here:
Explorations to America (Brazil)

This map, created by us, shows the two most important expeditions lead by the Kingdom of Portugal: Bartolomeu Diaz's and Vasco da Gama's.

Ver Portuguese Explorations en un mapa más grande