Shakespeare's main source for King Lear was The Chronicle History of King Leir (which was injected with Christian morals and images as opposed to Shakespeare's irreligious story). However, it has been claimed that his primary source can be traced as far back as Geoffrey of Monmouth's Historia Regum Brittaniae. Whether or not he read this in the original or gleaned what he could from other writers who used it as a source we cannot be sure. Monmouth was equally interested in the emotional and familial effect of dividing his kingdom as the political repercussions. However, Historia… is potentially more optimistic that Shakespeare's play. Here the husbands of Lear's elder daughters rise in insurrection against each other. Cordelia and Lier are reunited in France and eventually the King's lands are handed back to him. Three years later he dies and Cordelia is his heiress. Nonetheless the eventual outcome is still tragedy laden. Cordelia's nephews rebel against their aunt and place her in prison her where she commits suicide. The brothers then fall out with each other and civil war ensues. Only after a protracted period of time is there peace in England again.
The account of Lear and his daughters was told in a number of other literary works after this date, for example Higgins's Mirour for Magistrates, Holinshed's Chronicles, and (in passing) in Spenser's Faerie Queene. For his sub-plot Shakespeare drew upon Sidney's Arcadia. The original King Lier did differ in a number of ways from Shakespeare's play. The actions of Gloucester and his sons are based on those of Sidney's Paphlagonian King rather than the original source. Furthermore the characters of Oswald and the Fool are entirely absent from the original, as were Lear's madness and the storm.
Contemporary analogues also existed which Shakespeare clearly learned from, perhaps the most obvious being the life of Sir Brian Annesley. He was a servant to Queen Elizabeth and had three daughters, the youngest being called Cordell. His eldest daughter Lady Grace Wildgoose in an attempt to take over her father's affairs tried to have him certified as incompetent. With the help of Robert Cecil, Cordell tried to save her father who she believed deserved more respect in his old age. At his death in July 1604 his elder daughter contested his will but it was held to be correct