A turncoat is a person who shifts allegiance from one loyalty or ideal to another, betraying or deserting an original cause by switching to the opposing side or party. In political and social history, this is distinct from being a traitor, as the switch mostly takes place under the following circumstances:
 From a military perspective, opposing armies generally wear uniforms of contrasting colors to prevent incidents of friendly fire.  Thus the term "turn-coat" indicates that an individual has changed sides and his uniform coat to one matching the color of his former enemy.  For example, in the English Civil War during the 17th century, Oliver Cromwell's soldiers turned their coats inside out to match the colors of the Royal army (see Examples below).
 Even in a modern historical context "turncoat" is often synonymous with the term "renegade", a term of religious origins having its origins in the Latin word "renegare" (to deny). Historical currents of great magnitude have periodically caught masses of people, along with their leaders, in their wake. In such a dire situation, new perspectives on past actions are laid bare and the question of personal treason becomes muddled. One example would be the situation that led to the Act of Abjuration or Plakkaat van Verlatinghe, signed on July 26, 1581, in the Netherlands, an instance where changing sides was given a positive meaning.
 The first written use of the term meaning was by J. Foxe in Actes & Monuments in 1570: "One who changes his principles or party; a renegade; an apostate." Cited 1571*
 "Turncoat" could also have a more literal origin. According to the Rotuli Chartarum 1199–1216 two barons changed fealty from William Marshal, 1st Earl of Pembroke, to King John. In other words, they turned their coats (of arms) from one lord to another, hence turncoat.
 A mass-shift in allegiance by a population may take place during military occupation, after a nation has been defeated in war or after a major social upheaval, such as a revolution. Following the initial traumatic times, many of the citizens of the area in question quickly embrace the cause of the victors to benefit from the new system. This shift of allegiance is often done without much knowledge about the new order that is replacing the former one. In the face of fear and insecurity, the prime motive for a turncoat to draw away from former allegiances may be mere survival.
 Often the leaders are the first to change loyalties, for they have had access to privileged information and are more aware of the hopelessness of the situation for their former cause. This is especially apparent in dictatorships and authoritarian states when most of the population has been fed propaganda and triumphalism and has been kept in the dark about important turns of events.
 As time goes by, along with the embracing of life under the new circumstances comes a need of burying and rewriting the past by concealing evidence. The fear of the past coming to upset the newly found stability is always present in the mind of the turncoat. The past is rewritten and whitewashed to cover former deeds. When successful, this activity results in the distortion and falsification of historical events.
 Even after the death of a turncoat his family and friends may wish to keep uncomfortable secrets from the past out of the light. There is a fear of loss of prestige as well as a wish to honor the memory of a family member from the part of those who have experienced the positive side of the person.
 In certain countries, individuals and organizations have actively investigated the past to bring turncoats to justice to face their responsibilities.
 There were many turncoats in history, including: