 Following King Henry I 's death in 1135 , the succession was disputed between the king 's nephews — Stephen and his elder brother , Theobald II , Count of Champagne — and Henry 's surviving legitimate child Matilda , usually known as the Empress Matilda because of her first marriage to the Holy Roman Emperor , Henry V. King Henry 's only legitimate son , William , had died in 1120 . After Matilda was widowed in 1125 , she returned to her father , who married her to Geoffrey , Count of Anjou . All the magnates of England and Normandy were required to declare fealty to Matilda as Henry 's heir , but after the king 's death in 1135 Stephen rushed to England and had himself crowned before either Theobald or Matilda could react . The Norman barons accepted Stephen as Duke of Normandy , and Theobald contented himself with his possessions in France . But Matilda was less sanguine , and secured the support of her maternal uncle , the Scottish king David I , and in 1138 also that of her half @-@ brother Robert , Earl of Gloucester , an illegitimate son of Henry I. Nobles in the Welsh Marches revolted against Stephen in 1136 , but the revolt was not settled until 1138 . In 1139 , Matilda invaded southern England with her half @-@ brother 's support and the period of civil war began . 
 Following King Henry I 's death in 1135 , the succession was disputed between the king <a href='null_genetive' title='1'><mark>'s</mark></a>nephews — Stephen and his elder brother , Theobald II , Count of Champagne — and Henry <a href='null_genetive' title='2'><mark>'s</mark></a>surviving legitimate child Matilda , usually known as the Empress Matilda because of her first marriage to the Holy Roman Emperor , Henry V. King Henry <a href='null_genetive' title='3'><mark>'s</mark></a>only legitimate son , William , <a href='been_done' title='4'><mark>had</mark></a> died in 1120 . After Matilda was widowed in 1125 , she returned to her father , <a href='null_relcl' title='5'><mark>who</mark></a>married her to Geoffrey , Count of Anjou . All the magnates of England and Normandy <a href='uninflect' title='6'><mark>were</mark></a> required to declare fealty to Matilda as Henry <a href='null_genetive' title='7'><mark>'s</mark></a>heir , but after the king <a href='null_genetive' title='8'><mark>'s</mark></a>death in 1135 Stephen rushed to England and had himself crowned before either Theobald or Matilda could react . The Norman barons accepted Stephen as Duke of Normandy , and Theobald contented himself with his possessions in France . But Matilda was less sanguine , and secured the support of her maternal uncle , the Scottish king David I , and in 1138 also that of her half @-@ brother Robert , Earl of Gloucester , an illegitimate son of Henry I. Nobles in the Welsh Marches revolted against Stephen in 1136 , but the revolt was not settled until 1138 . In 1139 , Matilda invaded southern England with her half @-@ brother <a href='null_genetive' title='9'><mark>'s</mark></a>support and the period of civil war began . 
Following King Henry I 's death in 1135 , da succession was disputed between the king  nephews — Stephen and his elder homeboy , Theobald II , Count of Champagne — and Henry  surviving legitimate child Matilda , usually known as the Empress Matilda cuz of her first marriage to tdaHoly Roman Emperor , Henry V. King Henry  only legitimate son , William , done died in 1120 . After Matilda was widowed in 1125 , she returned to her father , married her to Geoffrey , Count of Anjou . All the magnates of England and Normandy was required to declare fealty to Matilda as Henry  heir , but after thdaing  death in 1135 Stephen rushed to England and had himself crowned before either Theobald or Matilda could react . Thedarman barons accepted Stephen as Duke of Normandy , and Theobald contented hisself wid his possessions in France . But Matilda was less sanguine , and secured the support of her maternal uncle , the Scottish king David I , and in 1138 also that of her half @-@ brother Robert , Earl of Gloucester , an illegitimate son of Henry I. Nobles in the Welsh Marches revolted against Stephen in 1136 , but the daolt was not settled till 1138 . In 1139 , Matilda invaded southern England wwher half @-@ homeboy  support and the period of civil war began .