The aim of my thesis is to study the rise of British naval mastery after the Napoleonic wars and the following process of decline from the second half of the 19th century till the Second World War. I will raise the question how such a relative quick rise after the Napoleonic era was possible and what the causes were for its decline. I will try to analyse those processes which caused these changes and how they influenced the nation. I will study the Royal Navy as the main force of defence to the Empire its colonies and as such its trade and its economy. However if we want to study the defence force of the Empire on the peek of its power it is necessary to give at least a brief overview on the main events of the previous centuries which made this quick rise possible.