Question: How many Royal families did Empress Matilda belong to?

<P0-S0> John FitzGilbert the Marshal of the Horses (c. 1105 – 1165) was a minor Anglo-Norman nobleman during the reign of King Stephen, and fought in the 12th century civil war on the side of Empress Matilda. <P0-S1>  Since at least 1130 and probably earlier, he had been the royal marshal to King Henry I. <P0-S2>  When Henry died, John FitzGilbert swore for Stephen and was granted the castles of Marlborough and Ludgershall, Wiltshire during this time. <P0-S3>  Along with Hamstead Marshal, this gave him control of the valley of the River Kennet in Wiltshire. <P0-S4>  Around 1139, John changed sides and swore for the Empress Matilda. <P0-S5>  In September 1141, Matilda fled the siege of Winchester and took refuge in the Marshal's castle at Ludgershall. <P0-S6>  While covering her retreat from Winchester, John Marshal was forced to take refuge at Wherwell Abbey. <P0-S7>  The attackers set fire to the building, and John lost an eye to dripping lead from the melting roof. <SEP> <P1-S0> In the Rout of Winchester (14 September 1141) the army of imprisoned King Stephen of England, led by his wife, Queen Matilda of Boulogne, Stephen's brother Bishop Henry of Blois, and William of Ypres, faced the army of Stephen's cousin Empress Matilda, whose forces were commanded by her half-brother Earl Robert of Gloucester. <P1-S1>  After Empress Matilda's army besieged a castle on the edge of Winchester, Queen Matilda's army arrived and blockaded the Angevin army within the city. <P1-S2>  Cut off from supplies, the Angevin army gave up the siege, then was crushed as it began to retreat. <P1-S3>  Robert of Gloucester was captured and was subsequently exchanged for Stephen, who was returned to the throne of England. <P1-S4>  However, the civil war known as The Anarchy dragged on with neither side gaining an advantage. <SEP> <P2-S0> Empress Matilda (c. 7 February 110210 September 1167), also known as the Empress Maude, was the claimant to the English throne during the civil war known as the Anarchy. <P2-S1>  The daughter of King Henry I of England, she moved to Germany as a child when she married the future Holy Roman Emperor Henry V. <P2-S2>  She travelled with her husband into Italy in 1116, was controversially crowned in St. Peter's Basilica, and acted as the imperial regent in Italy. <P2-S3>  Matilda and Henry had no children, and when Henry died in 1125, the crown was claimed by Lothair II, one of his political enemies. <SEP> <P3-S0> Geoffrey V (24 August 1113 – 7 September 1151) — called the Handsome or the Fair (French: "le Bel" ) and Plantagenet — was the Count of Anjou, Touraine, and Maine by inheritance from 1129 and then Duke of Normandy by conquest from 1144. <P3-S1>  By his marriage to the Empress Matilda, daughter and heiress of Henry I of England, Geoffrey had a son, Henry Curtmantle, who succeeded to the English throne as King Henry II (1154-1189) and was the first of the Plantagenet dynasty to rule England; the name "Plantagenet" was taken from Geoffrey's epithet. <P3-S2>  His ancestral domain of Anjou gave rise to the name Angevin for three kings of England (Henry II his son and heir, and Henry's sons Richard and John), and what became known as the Angevin Empire in the 12th century.