Born "Prince August Viktor Ludwig of Saxe-Coburg-Saalfeld", he was the second son of Prince Ferdinand of Saxe-Coburg and Saalfeld. He was born in Vienna on 13 June 1818 and baptised at St. Stephan Cathedral on the 16th of that month. His godparents were his paternal grandmother, Countess Augusta Reuss of Ebersdorf, his aunts, Victoria, Duchess of Kent and Louise, Duchess of Saxe Coburg. Following the 1826 re-distribution in the House of Wettin of the Ernestine duchies, his dynastic suffix became "of Saxe-Coburg and Gotha". His mother was Princess Maria Antonia Koháry, the daughter and heiress of Ferenc József, Prince Koháry de Csábrág et Szitnya. When Antonia's father died in 1826, she inherited his estates in Slovakia and Hungary. Prince August was a younger brother of King-Consort Ferdinand II of Portugal, a nephew of Leopold I of Belgium, and a first cousin of Britain's Queen Victoria, and her husband, Prince Albert.