The real (meaning: "royal", plural: reais later becoming réis) was the unit of currency of Portugal from around 1430 until 1911. It replaced the dinheiro at the rate of 1 real = 840 dinheiros and was itself replaced by the escudo (as a result of the Republican revolution of 1910) at a rate of 1 escudo = 1000 réis. The escudo was further replaced by the euro at a rate of 1 euro = 200.482 escudos in 1998.
The first real was introduced by Ferdinand I in around 1380. It was a silver coin and had a value of 120 dinheiros (10 soldos or ½ libra). In the reign of King João I (1385–1433), the real branco of 3½ libras and the real preto of 7 soldos (one tenth of a real branco) were issued. By the beginning of the reign of King Duarte I in 1433, the real branco (equivalent to 840 dinheiros) had become the unit of account in Portugal. From the reign of Manuel I (1495–1521), the name was simplified to "real", coinciding with the switch to minting real coins from copper.
In 1837, a decimal system was adopted for the coin denominations, with the first banknotes issued by the Banco de Portugal in 1847. In 1854, Portugal went on to a gold standard of 1000 réis = 1.62585 grams fine gold. This standard was maintained until 1891.
Large sums were usually expressed as "mil-réis" (sometimes "milréis") or 1,000 réis, a term often found in 19th century Portuguese literature. In figures a mil-réis was written as 1$000, so that 60,000 réis would be written as 60$000 or 60 mil-réis.)
In 1911, the escudo replaced the real. One million réis was known as a conto de réis. This term survived the introduction of the escudo to mean 1000 escudos and is now used to mean five euros, almost exactly the converted value of 1000 escudos or one million réis (precisely 1 conto = 4.98797897€).
Coins and banknotes were also issued denominated in réis for use in the different parts of the Portuguese empire. See: Angolan real, Azorean real, Brazilian real, Cape Verde real, Mozambican real, Portuguese Guinea real and São Tomé and Príncipe real. Brazil has revived the real as the denomination of its present currency.
Before the middle of the 19th century, many different denominations were minted, often with values in terms of the real which increased over time. For example, the cruzado was introduced at a value of 324 real branco in the reign of João II. It was fixed at a value of 400 réis during João III's reign and this remained the value of the silver cruzado until the reign of Pedro II, when it was revalued to 480 réis. Meanwhile, the gold cruzado rose in value to 750 réis in the reign of João IV, then to 875 réis in the reign of Afonso V before its demise. Two denominations which did not change their values were the vintém of 20 réis and the tostão of 100 réis.
The last 1 real coins (excluding colonial issues) were minted in the 1580s. After this time, the smallest coins were worth 1½ réis. These were minted until around 1750, after which the three réis coin became the smallest circulating denomination. From the early 18th century, the standard gold coin was the peça, valued at 6400 réis (7500 réis after 1826).
In the late 18th century and early 19th century, copper coins were issued in denominations of 3, 5, 10, 20 and 40 réis, with silver 50, 60, 100, 120, 240 and 480 réis and gold 480, 800, 1200, 1600, 3200 and 6400 réis. Some of these coins showed denominations which were no longer accurate due to earlier revaluations. These included the 240 and 480 réis which were inscribed 200 and 400.
In 1837, a decimal system was adopted, with copper coins (bronze from 1882) of 3, 5, 10 and 20 réis, silver coins for 50, 100, 200, 500 and 1000 réis and gold 1000, 2000, 2500, 5000 and 10,000 réis. In 1875, the last 3 réis coins were issued, with cupro-nickel 50 and 100 réis issued in 1900.