Though sovereign debts are often viewed as risk-free assets, some extreme events may lead to the repudiation of these debts. A large literature has been devoted to the motivations of repayment and to the causes of default. The impact of wars, which may lead to the repudiation of sovereign debt, on sovereign bond prices has also been analyzed. However, the impact of other types of seldom occurring but dramatic events, which may lead to the repudiation of debts, on bond prices has been overlooked. My current research aims to analyze three of them: the repudiation of debts because of their alleged "odiousness", the introduction of common debt after a state's unification and the debt partition following the break-up of a country. Since the events under consideration don't happen frequently, the dissertation will rely on four historical examples: Cuba, Russia, Italy and Belgium. The time period considered is the 19th century. Based on a historical analysis and the set-up of an original database, this project determines the effects of these events on sovereign debt valorization, using an econometric approach. The first part of the research estimates the risk premium required by investors to hold debts which could be denounced as odious. Bondholders could require a premium to compensate for the higher default risk due to the odious character of the debts. The paper quantifies the risk premium required by investors to hold debts which could be denounced as odious and it analyses the relation between the value of the government bond and extreme "odious debt" events. In order to identify if such a premium exists, I focus on a Cuban case study. Based on an original database of Cuban bonds, the paper reveals the existence of a risk premium of at least 200 basis points which penalises bonds issued by dictatorial regimes. The bond market "odious" shocks are provided by a Structural VAR analysis. In a second case study, my research analyses the Tsarist bonds of 1906 and the premium to hold despotic regime debt. The paper shows ...