IDA DE LORRAINE (c1040-1113) a.k.a. Blessed Ida of Boulogne Regent of Boulogne for her son, Eustace III, Count of Boulogne, 1087-1125, when he went on the Crusade.
"...Urban II's call to crusade in 1095 mobilized many French noblemen, including the sons of Eustace II and Ida of Boulogne---Eustace, Godfrey, and Baldwin... The crusaders spent most of 1096 preparing for their bellicose pilgrimage: choosing regents and gathering funds and men for the long expedition... Eustace left his mother as regent of the county...." (Tanner, p. 135)
IDA VAN LOUVAIN (1077-1139) Regent of Hainaut, 1098-1103, for her son Baldwin IV of Hainaut
IDA VON SPONHEIM (d.1178)
Regent of Nevers, 1147-1149, when her husband joined the Second Crusade She was the daughter of Engelbert of Sponheim, Duke of Carinthia She was the wife of Guillaume III, Count of Nevers Read more here and here.
INGARD VON POMERANIA(d. after 1236) Regent of Pomerania, 1219-1221, for their son, Wartislaw III (1210-64) She was possibly a princess of Denmark. She was the wife of Kasimir II (1180-1220), Duke of Pomerania-Demmin.
INGEBORG OF NORWAY (1301-1361)
[Bio1] Regent of Sweden, 1319-1326, for her son Magnus IV of Swedenm (jointly with Magnus’ grandmother, Hedwig of Holstein). Regent of Norway, 1319-1327, for her son Magnus VII of Norway
"Magnus Eriksson, the son of Duke Erik and Ingeborg, was only three years old when his grandfather died, and the government therefore fell into the hands of a regency, the members of which had already been designated by King Haakon. Shortly before, a rebellion had broken out in Sweden against King Birger... He was deposed... At the instance of the regent, Mats Kettilmundsson, Magnus Eriksson was proclaimed King; and Norway and Sweden were thus for the first time united under one ruler. The union was a mere nominal one... During Magnus' minority, however, his mother, Duchess Ingeborg, governed in Norway with the utmost recklessness, making great scandal by her love of the Danish nobleman Knut Porse, duke of Halland, whom she married later. To enrich him she squandered the revenues and forfeited her populatiry... [T]he duchess was a last deprived of her power, and Sir Erling Vidkunsson of Bjarko and Giske was made regent in her place." (Boyesen, pp. 460-461) (See also Echols & Williams, p. 226)
INGEMUND Regent of Man, 1096-1098 (jointly with Domnall Mac Teige)
Iñigo Fernandez de Velasco, Duke of Feria Governor of the Netherlands, 1668-1670
Cardinal Giuliano de' Medici, Pope Leo X
Cardinal Innocenzo Cibo Innocenzo Cibo (1491-1550) Cardinal, 1513 Governor and Regent of Florence, 1532-1533, during the absence of Duke Alessandro. Regent of Florence, 1537, after the assassination of Duke Alessandro. Protector of Germany, 1542 Regent of Massa and Carrara, 1547
IOSAF, Archbishop of Moscow (d. 1555) Regent of Russia, 1540-1542, for Ivan IV of Russia
IPPOLITA CYBO OF FERENTLLO (1495-?)
Daughter of Franceschetto Cybo, Count Palatine of the Lateran. Married 1522 Roberto Ambrogio Sanseverino (1490-1532), 3rd Count of Cajazzo.
Regent of Sanseverino for their sons, 1532-39, 1539-44.
IPPOLITA MARIA SFORZA (1446-84) wife of Alfonso of Aragon, Duke of Calabria Regent of Bari, 1479-1484
Regent of Byzantium, 780-790, 792-797, for her son Constantine VI, Empress of Byzantium, 797-802, after ousting her son, becoming the first woman ever to hold the throne of the old Roman Empire.
"The eighth century Empress Irene solved the problem by simply refusing to stand aside for her son, Constantine VI, once he reached adulthood. After an uneasy period of joint rule and political conflict, Irene’s supporters deposed and eventually murdered Constantine - to pave the way for a period of sole rule by Irene. Irene is generally treated as a notorious character due to the murder of her son. But the fact remains that she was one of few Byzantine women ever to rule the Empire in her own right; even to the extent of taking the male title Basileus (Emperor) in preference to the usual official status of Empress.“ "...She becomes the first woman to rule the Byzantine Empire in her own right and takes the title 'basileus' (king). She reduces taxes, sponsors public works, and distributes charity, becoming popular with the common people." (Olsen, 1994, p. 33)
IRINA FYODOROVNA GODUNOVA Regent of Russia, 1598, for Feodor I of Russia
ISABEAU VON BAIERN Regent of France, 1417-1420, for her son, Charles VI of France
Isabel of Brazil (1846-1921) Regent of Brazil, 1871-1872, 1876-1877, 1887-1888, for her father, Pedro II of Brazil when he was away from the country.
Regent of Spain, 1529-1533, 1535-1538, for her husband, Carlos I of Spain (Emperor Karl V).
"The daughter of Maria of Aragon and Manuel of Portugal, Isabel of Portugal was Charles's cousin. She was also a true 'daughter' of Isabella of Castile. When Charles was forced to leave Spain for the empire, he appointed his wife as his regent, a role she fulfilled admirably. The Cortes recognized her position on 27 July 1527. She took her duties as regent seriously and was personally involved, as well, in the education of her two children, Philip, born in May 1527, and Maria, born in 1528. Charles returned to Spain in April 1533, and when he left again in April 1535, Isabel was regent once more. But after Isabel's early death in 1539, at the age of thirty-six, Andrew Wheatcroft indicates Charles was 'hamstrung' because he 'could find no one to replace her effectively.'...." (Jansen, p. 105)
Regent of Transylvania for her son Janos II Sigismund Zapolya. Regent of Hungary, 1540-1541, 1556-1559, for Janos II Zsigmond Szapolyai.
"..."[T]he Sultan [Suleiman]...seized upon Buda, 1541-1551, 1555-1558, and obliged Isabella to retire to Lippa...In this reverse of fortune, Isabella displayed great constancy, and endeavoured to content herself with the title of Regent of Transylvania, which the rapacity of Solyman had left her. But, having appointed as her coadjutor in the administration of the government, George Martinusias, a monk, she experienced from him a thousand mortifications, and found the title of regent but an empty honour. A rupture with Martinusias was the consequence; when, eneraged at the loss of his authority, he called in the assistance of Ferdinand of Austria, who sent an army into Hungary, and compelled Isabella, in 1551, to resign Transylvania into his hands, and to retire to Cassovia. While on her journey to Cassovia, the ruggedness of the roads obliged her to descend upon her carriage; when looking back to Transylvania while the driver was extricating his wheels, and recollecting her former situation, she carved her name on a tree, with this sentence---'Sic Fata volunt'---'So Fate decrees.'...In 1556, she was, by the efforts of the Sultan, restored to Transylvania. She maintained her authority during the rest of her life, without imparting any share of it to her son, John Sigismund. She died September 5th., 1558)" (Adams and Hale, p. 405)
ISABELLA CLARA VON OSTERREICH (1629-1665) Regent of Mantua, 1665-1669, for her son Charles IV, Duke of Mantua.
"...Charles Ferdinand was only thirteen years old when he succeeded his father. Thus, his mother the Archduchess Isabella Clara of Austria became the first guardian and regent of the state. After the death of her husband, she continued to rely on the advice of Count Bulgarini, her lover, and a prominent figure in the cultural life. After her son's attainment of majority, Isabella Clara retired to the palace of Evansville where her relationship with the Bulgarini continued. After Bulgarini he escaped an assassination attempt, the duchess was forced to enter the monastery of Sant'Orsola (where she died in 1685) while the count was locked in the convent of San Domenico." Ittocorre Gambella, Regent of Logudoro, 1127-1140, for Gonario II of Torres who was about 14 years old when his father died.
ISABELA CLARA EUGENIA DE ESPANA Governor of the Netherlands, 1598-1633
ISABELLA D'ESTE (1474-1539)
Regent of Mantua, 1509-1510, for her husband, Francesco II
Regent of Mantua, 1519-1521, for their son, Federico II of Mantua.
"...When Francesco was captured and imprisoned by the Venetians (August 1509-July 1510), Isabella acted as Mantua's sole regent, successfully fending off foreign contenders for Gonzaga territories...Isabella's duties included presiding over the Mantuan court in her husband's absence...." (Robin et. al., p. 132)
ISABELLE I DE LORRAINE (1400-1453) Duchess of Lorraine, 1431-1453
She was the daughter of Charles II of Lorraine. She married in 1420, at age 13, Rene of Anjou.
"...She united to great beauty, intellect, generosity, and courage. When her husband was taken prisoner by the Duke of Burgundy, in 1429, she assembled the nobles of Lorraine, placed her four children under their protection, and raised an army to rescue her husband. While he was still a prisoner, the kingdom of Sicily, by the death of Charles the First, became his; and Rene sent Isabella to claim it. She went there, and by her wise and skilful (sic) government acquired great popularity. In 1437, Rene joined her; but in less than five years he was forced to return with his family to France by his victorious rival, Alphonso of Arragon (sic)...." (Adams, ed., p. 404)
"In Sicily, Isabelle of Lorraine (fl. 1420s-1440s) had assumed the title of the Queen of the Two Sicilies and had asserted her husband's right to rule there, functioning as his regent while he was imprisoned...." (Jansen, p. 245)
ITTOCORE DI TORRES
Co-Regent of Torres with his three brothers, 1147-1149 when his father, Gonario II, joined the Second Crusade.
Regent of Torres, 1127-1140, for Gonario II of Torres who was a minor when his father, Constantino I, died.
Ivo II the Elder (d.1178) Count of Soissons, 1146-1178 and Lord of Nesle (as Ives III) Regent of Vermandois, 1152-1160?, during the minority of Raoul II of Vermandois (1145-1167), known as the Younger or the Leper, Count of Vermandois and Valois, 1160-1167, who was only about 7 years old when his father, Raoul I of Vermandois (1085-1152), died.
JACOB DE LA GARDIE Regent of Sweden, 1632-1644, for Christina of Sweden
Ivan Fyodorovich Belsky (d. 1542)Regent of Russia, 1530-1542, for Ivan IV of Russia
Ivan Fyodorovich Mstislavsky (d.1586)
Regent of Russia, 1584, for Feodor I of Russia
Ivan Fyodorovich Ovchina Telepnyov-Obolensky (d.1539) Regent of Russia, 1534-1538, for Ivan IV of Russia and lover of Elena Glinskaya.
"Ivan Vasil'evich, better known as Ivan IV or Ivan the Terrible, was born on August 25, 1530... He was the son of Grand Prince Vasilii (Basil) III, the titular ruler of what was still known then as the Kingdom of Muscovy, and Ielena Glinskaia, member of the well-known boyar (princely) family of Glinskiis... Ivan's father died when he was but three years old and his mother ahd her lover, Prince I. Ovchina-Telep-ev Obolenskii, ruled as regetns until 1537, when apparently she was poisoned by boyar plotters...." (Blumberg, p. 126)
Regent of Russia, 1584-1587, for Feodor I of Russia.
Ivan Vasilyevich Shuisky (d.1542) Regent of Russia, 1538-1542 and 1542, for Ivan IV of Russia.