The reason vampires are naturally weak against the sun, actually started at the time of the Originals, when the witch Esther used the sun's life aspect and the White Oak tree's immortality to make her family live forever and be able to protect themselves. Sunlight is harmful but not fatal to Originals, however, Esther created the very first daylight rings.
Some vampires have charmed daylight jewelry with Lapis Lazuli; these rings must be forged by witches because the Lapis itself is simply a stone. It protects them from the sunlight. So long as the vampire wears it in the sun, he or she can't die from exposure. Both Stefan and Damon Salvatore are in possession of rings containing Lapis Lazuli which protect them from the harmful effects of the sun. However, without such a ring sunlight will burn a vampire on contact. During Damon's imprisonment, Stefan deprives him of his ring so when he later tries attacking Caroline and runs into a shaft of sunlight, he's left with nasty facial burns following exposure of approximately 3 seconds.
Slater's cafe and home contained tempered glass windows to block UV rays, making them safe environments for vampires. This shows the harmful element is natural UV light, but it is unclear if artificial UV light would have the same effect. Furthermore, it's unclear if the lapis lazuli rings protect against only natural sunlight or UV rays in general.
- In the series, Isobel Flemming is the first vampire seen to actually die from sun exposure.
- In the novels, Katherine von Swartzschild is the first vampire die from sun exposure, as well as Elena Gilbert, but she died of "poisoning" sunlight.
- Known vampires that have been damaged by sunlight are: Alaric Saltzman, Damon Salvatore, Ben McKittrick, Caroline Forbes, Rose, Katherine Pierce, Isobel Flemming, Rebekah, Elena Gilbert, Slater, Alexander's prey.