Peter II (Portuguese Pedro), the Pacific (Port. o Pacífico) (April 26, 1648 – December 9, 1706), Regent (1668 – 1683) and 23rd (or 24th according to some historians) King of Portugal and the Algarves (1683 – 1706).

The youngest son of João IV and being created Duke of Beja, he was appointed regent for his insane brother, Afonso VI, in 1668, shortly after Spanish recognition of Portugal's independence. Peter first locked his brother away, but came to the throne in his own right after Afonso's death in 1683. Around this time, the discovery of gold mines in Brazil enlarged Peter's treasury to the extent that he was able to dismiss the Cortes in 1697 and rule without its revenue grants for the rest of his reign.

Initially Peter supported France in the War of Spanish Succession (1702 – 1715), but on May 16, 1703, Portugal and Britain signed the famous Methuen Treaty. This trade accord granted mutual commercial privileges for Portuguese wine and English textile traders and would later give Britain huge clout in the Portuguese economy. This was followed in December 1703 by a military alliance between Portugal, Austria and Great Britain for an invasion of Spain. Portuguese and Allied forces, under the command of the Marquês das Minas, captured Madrid in 1706, during the campaign which ended in the Allied defeat at Almansa.

Peter not only inherited his brother's throne but also married his wife, Queen Marie - Françoise of Savoy (1646 – 1683). They had one daughter, Princess Isabella Louise (1669 – 90), princess of Beira and heiress - presumptive, a.k.a "a Sempre - Noiva" (the ever - engaged), because of the many marriage projects intended for her that were never completed. The Queen, apparently incapable of birthing more offspring, died at the end of 1683, 14 years after Isabella's birth. Because the Princess was a fragile and sick child, the King decided to marry again.

The chosen bride was Maria Sophia (1666 – 1699), daughter of Phillip William of Neuburg. Among Sophia's sisters were Eleonor Madeleine, wife of Leopold I of Austria and Maria Anna, second wife of Charles II of Spain.

This marriage was concluded, and the couple had eight children, including the new viable heir to the throne, the younger John, who eventually succeeded his father, after his death in 1706, as King John V of Portugal.