A guy called Alfred Hitchcock did it first in a little movie called Psycho...and he was English ;)

The movie is defined as technically the first slasher movie and influenced the modern slasher films such as Halloween.

Maybe Psycho can be considered the first slasher film. I'm not sure I would agree with that. Regardless, I have read that Psycho was influenced by Les Diabolique (1954) and Dead of Night (1945).

I was watching one of those all time top horror and thriller film thingies on the TV. Many well known horror directors listed it, and went on to say how it spawned the slasher genre and influenced their films. Wes Craven and John Carpenter were two of those guys.

But yeah I expect even Psycho had influences, and those influences had influences too :)

im sure most early films were influenced by true stories that were just tweaked a little bit.

slasher movies are a no brainer really - as far as the core influences/inspirations come from.

what scares people ... the thought of someone killing you.

what scares you in a film : the technique used to present this to you.

technique is the only real measurable when it comes to who influence who.

so i would say yes - hitchcock perfected the technique of suspense in a horror film,

the others that followed each put their own little tweak on it ..

Bay of Blood = brutality
Halloween = the killer who couldnt be killed
Black Christmas = the killer inside your house..

etc etc ..

the ones that stand out and became popular are the ones who had their own unique angle.

(more atmospheric music, better performances, more inventive kills)

Yeah. God bless that the genre was created thats all I can say :)

in my perspective slashers are the best type of horror out there.