People talk about Halloween (1978) being the daddy of all slasher films, and Psycho being the granddaddy, but there's a much longer history of slashers in film, going almost all the way back to the silent era. First came the golden age movies like M (1931), Thirteen Women (1932), and And Then There Were None (1945), the original slasher movies. Golden Age Slashers were old school horror movies which set up the basic prototype of a villain killing off people one by one in a remote location. These don't look like modern slashers but if we watch them closely and analyze them we see the basic ingredients and formulas which the modern slasher would follow. Golden Age Slashers gave us the plot structure of slashers; but the murders were usually off screen and they didn't fixate on a horrific figure stalker as much as later iterations. But the basic plot is still there. For example, you can see how And Then There Were None set up the basic plot structure of Friday the 13th. We can see how 13 Women informed Black Christmas later; it's the same plot; without the gory Grand Guinol ingredients of Black Christmas. Then after that there were classic age slashers, films from the 1950s and 1960s such as Psycho (1960) and Diabolique (1955), as well as Buckets of Blood (1959), and Straight Jacket (1964); which would help create the prototype for slashers as well. The Classic Slashers followed in the trend of the golden age slashers but they fixated more on the horror of the deaths themselves; and more on a horrific villain. And Then There Were None has some of the basic plot ingredients of Psycho; but Psycho fixated on Norman/mother more than And Then There Were None focused on Judge Wargrave; and Psycho actually show's the extended shower murder sequence; whereas in And Then There Were None these are all off screen. Then later in the 1960s in Italy the Giallo movie started; these pushed the envelope for gore in the modern era with movies like A Bay of Blood (1971). At the same time in America, in the 1960s, Hershell Lewis, a business man and entrepreneur, decided to break into film and direct movies that were built around gorey set pieces; the new so called splatter movies. These movies were shown almost exclusively in drive-ins, and so were able to avoid the censorship issues that normal theater chains had. The first of the splatter genre was called Blood Feast, and it came out in 1963 and it was indeed the first modern gore movie in American cinema. That led to other splatter movies with titles like Gruesome Twosome and The Wizard of Gore, all produced by Hershell Lewis (there were only 7 of them as a matter of fact). The effect of the splatter movies and Giallo would bleed into mainstream American horror; and the next group of slashers, after Giallo/splatter in the 1960s, would be the American modern slashers, starting with The Texas Chain Saw Massacre (1974) and Black Christmas (1974); both followed by the seminal classic slasher Halloween (1978); and finally Friday the 13th (1980). The modern slashers have all the classic and basic ingredients of what we now see as the "Slasher Horror Movie"; teenagers in peril being picked off by an unseen assailant, gory deaths, the final girl and her battle with the villain, etc. The period directly after that would be the post-modern slashers, or the Mehta Slasher, starting with Scream (1996). Scream used the same ingredients of the modern slasher but added Mehta in-jokey references to let the audience know they were in on how hokey the genre was. This genre was birthed by Scream screenwriter Kevin Williamson; and it singlehandedly resurrected the slasher movie and was very popular for about a decade. At a certain point people got sick of all the Mehta in joke references though, and they hungered for sincerity in the dialogue, not just sarcasm all the time, and so that trend died off in the late naughties. In the late 90s there was another trend which followed with the modern/Mehta slasher; and that was the "Found Footage" trend; which would see our teens in peril recorded on a video camera. Those movies were mostly supernatural thrillers like Blair Witch Project and Cloverfield. The only slasher that would fall into that subcategory would be "Halloween :Resurrection". Then there was the so-called "torture porn cinema era". Torture porn was in some ways returning to the glory days of the 60s Splatter movie; which still had teens and young adults chased and terrorized by an assailant; but as with Splatter the deaths in these movies emphasized prolonged scenes of Gore and torture. Torture porn started with Saw (2004); and would continue with Hostel (2005), Touristas (2009); and then it fizzled out in the late naughties and the teens. And that would then bleed into the era we're in today; the Reboot Era; which would start with 2003s The Texas Chainsaw Massacre; and would continue with 2009s Friday the 13th as well as the big blockbuster of this era; 2018s Halloween. These were still Slashers, but instead of original stories they focus on rebooting classic movies in the horror cannon from the 70s, 80s and 90s.