Dynastic marriages between reigning Houses of Europe have always played an essential role in the foreign policy of countries, consolidating their cooperation. The defeat of Napoleon by the Russian Emperor Alexander I in the Patriotic War of 1812 proved the feasibility of liberation of Europe from France’s oppression and created favourable conditions for the British Prince Regent George, future king George IV of the United Kingdom, and the Dutch Prince William of Orange, future king William I of the Netherlands, to embark on the realization of a dynastic alliance between their children - Princess Charlotte of Wales and Hereditary Prince William of Orange. However, even though nearly all necessary preparations were made, the British-Dutch dynastic alliance plan collapsed in June 1814 on the initiative of the wayward Princess of Wales. That played into the hands of Alexander I who set sights on the Dutch Hereditary Prince as a prospective spouse for his younger sister Grand Duchess Anna, and the Tsar did not want to yield to England. In the article the author, by using archival sources most of which are of Dutch origin, reveals the mutual interests of the Netherlands and Great Britain which determined the idea of a dynastic marriage, analyses the possible role of Alexander I in its failure that eventually paved the way towards the Russian-Dutch dynastic alliance.