Alternate history or alternative history (Commonwealth English) (AH) is a genre of speculative fiction consisting of stories in which one or more historical events occur differently. These stories usually contain "what if" scenarios at crucial points in history and present outcomes other than those in the historical record. The stories are conjectural but are sometimes based on fact. Alternate history has been seen as a subgenre of literary fiction, science fiction, or historical fiction; alternate history works may use tropes from any or all of these genres. Another term occasionally used for the genre is "allohistory" (literally "other history").