The definition of a "feature" evolved during the silent era. For US movies, I consider "The Great Train Robbery" (1903) as the first "feature" (even at only 12 minutes), because it told a story, rather than just demonstrating the new technology, (like Edison's "The Kiss"). In France, of course, Georges Méliès and Alice-Guy Blaché were making "story" films (again, short ones) before 1900. In 1912, "Quo Vadis?" (Italy) and "Queen Elizabeth" (France) began to change things, leading to the creation of "movie palaces"--theaters of the type we know today. This change was cemented by films such as "Tillie's Punctured Romance" (1914), "Cabiria" (Italy, 1914), and (ugh) "The Birth of a Nation". Short subjects continued to proliferate, but they aren't included here.
I've oversimplified the above a bit (character limit), and you're free to disagree with my definition of "silent feature" and create your own list. In fact, I welcome and look forward to seeing and participating in other lists.