Albert VII, Archduke of Austria

Albert VII, Archduke of Austria (13 November 1559 – 13 July 1621) was an Austrian prince and an archduke of the Hapsburg dynasty at the height of that family's power in the sixteenth and seventeenth centuries. He served his family as the ruler of the Hapsburg Netherlands from 1595 until his death in 1621. He first ruled his family's holdings in the southern Low Countries and northern France as Governor. He was Archbishop of Toledo from 1595 until 1598, when a dispensation by the Church allowed him to leave the clergy in order to marry his first cousin, Infanta Isabella of Spain, the daughter of King Philip II. As husband and wife they reigned over the Hapsburg Netherlands as co-sovereigns.

Albert in Ruled Britannia
King Albert I of England, also known as Albert Hapsburg or Albert of Austria, was an Austrian prince of the Hapsburg dynasty. He was a nephew of Spanish King Philip II and a cousin of his daughter, Isabella. Albert married Isabella some time after the Spanish Armada conquered England in 1588, and as the Spaniards had imprisoned Elizabeth I in the Tower of London and proclaimed Isabella the new Queen, Albert became King of England by marriage. However, Albert was seen mostly as an appendage of his wife and was not taken seriously as a ruler in his own right. The couple were in turn subservient to Philip II of Spain, even though England remained legally a realm separate of the Spanish Crown.

The reign of Albert and Isabella saw the restoration of Catholic rule in England, the establishment of the English Inquisition to enforce Catholic orthodoxy among the English and the introduction of Pope Gregory XIII's new calendar in the island. Their position, however, was entirely reliant on a Spanish occupation army led by Don Diego Flores de Valdes and the collaboration of English notables whose profession of Catholicism was often phony. When the English rose in revolt and crushed the Spaniards in 1598, Albert and Isabella narrowly escaped England with their lives and Elizabeth was restored. During Albert and Isabella's decade-long reign, silver and copper coins bearing the image of the royal couple circulated in England, though they never displaced the coins bearing the image of Elizabeth completely.

Literary comment
In OTL, Albert did not marry Isabella until 1598, while in Ruled Britannia he has been her husband for a while before 1597. This is explained by Harry Turtledove in the novel's afterword: Philip II had intended to marry his daughter to an Austrian prince long before that date, and Albert was the most obvious candidate. With Isabella needing to solidify her position as Queen of England, she would likely marry earlier and try to have children as soon as possible. The couple does not seem to have been more lucky in the novel than in OTL, where all their children were miscarried or died in infancy.