Anthony Hope

English trout fisher Rudolf Rassendyll is about the only tourist not coming for the coronation of Central-European King Rudolf V at Strelsau, but happens to be a distance relative and is approached on account of their canning resemblance to stand in for the drunk king... (imdb)

This is a classic swashbuckler. Rudolph Rassendyll, Rudolf V's identical distant cousin, is asked to risk his life and impersonate the would-be king when his relative is kidnapped before his impending coronation. If Rudolf V isn't present at the ceremony, he will forfeit the crown to his younger brother. Complications ensue when Princess Flavia, the cousin's betrothed, begins to notice a "personality change" in her fiancé. (imdb)

This epic-scale silent adaptation of the popular novel by Anthony Hope concerns Rudolph (Lewis S. Stone), a member of the royal family of Ruritania who is about to be crowned King. However, his conniving and ill-tempered brother Rupert (Ramon Novarro) has designs on the throne, and he poisons his brother shortly before his coronation... (All Movie Guide)

King Rudolf of Ruritania is saved from a coup attempt by the help of his lookalike cousin, who falls in love with the king's fiancee. (imdb)

An English tourist poses as his royal double to foil revolutionary kidnappers (imdb)

The King of Ruritania is kidnapped by his scheming brother: can his British double save him? (imdb)

A person comes to meet with Gauri Shankar Roy (Uttam Kumar) living in Kolkata. He introduces himself as a 'fauji Sardar' of Jhind, Jhind being a small kingdom in Madhya Pradesh. He says that the to-be king of Jhind, Shankar Singh, is found missing from the kingdom right before his 'abhishek'(oath taking of a king) and this is apparently a conspiracy by his own brother Udit Singh, who wants the kingdom for himself. (imdb)