There are two steps to becoming a vampire in The Vampire Diaries. First tu must have vampire blood in tu and after that tu must die. Then whn tu die it gives tu time to transform. So Kathrine had gotten her blood into the Salvatore brothers before thy took her. So some how Damon and Stefan died.Like in the book it says that they were in a sword fight and thats how they died and became vampres but thats the book not the show.
yes damon and stefan had tkatherines blood in there systems then when they were fightin eachother they ended up killin one another but instead of dyin they turned into vamps cause they had vampire blood in them
it was Katherine who turned the amor of my life and Damon into vampires. i know this because my dear Stefan told me. and, yes, vampiros are REAL. watch out, because Vampire Diaries and Twilight were based on REAL stories. be aware for newborns in the woods, and other killer vampiros like possibly Damon.
kathrine did turn them and he was not put in the tumb they just thought she was. when damon and stephan were shot they had her blood in there system so they woke up and had tofeast on human blood to complete the transformation.