A Crossover Episode is the placement of two or more shows combining the characters, settings or universe into a single episode conjoined with either a spin-off or an entirely different series. In this case, The Originals is the spin-off of the The Vampire Diaries as The Original family was associated with the parent show, until the storyline developed and The Originals had succeeded with their own show. The same way Hope Mikaelson's storyline from The Originals continues in Legacies.
For a list of actors/actresses who appeared in TVD/TO/Legacies and another show/film see: Cast Crossovers.
Several Crossover episodes have occurred during the previous seasons. They are listed in chronological order.
List of episodes
|The Vampire Diaries, 4x20. This episode is the official Pilot to The Originals. Klaus returns to New Orleans until he discovers his unborn child, his former protégé, now king of New Orleans, and his families' deep buried secrets.|
| ||The Originals, 1x07. Tyler visits New Orleans, intent on gaining his vengeance on Klaus and killing his unborn child.|
| ||The Originals, 1x08. Tyler continues with his plans, until obstacles destroy his path and is ultimately thrown in The Garden.|
| ||The Vampire Diaries, 5x11. The parent show's hundredth episode; Katherine is deteriorating though Klaus and Rebekah decide to visit. Rebekah has an encounter with Matt, Klaus had his wish with Caroline and Elijah appears as Katherine's hallucination.|
| ||The Originals, 2x05. We finally learn the origins of Tatia, a Petrova Doppelgänger who has a history with the Original family. She was mentioned in Season 2, 3 and 4 of TVD. Tatia's flashback sheds light on how the mythology we knew as viewers was all lies.|
| ||The Vampire Diaries, 7x14, This is part of a two hour crosssover with The Originals. Stefan visits New Orleans to seek safe haven from a hunter named Rayna Cruz.|
| ||The Originals, 3x14, This is part of a two hour crossover with The Vampire Diaries. Stefan visits New Orleans to seek safe haven from a hunter named Rayna Cruz.|
| ||The Originals, 3x17, the kidnapping of Freya is instrumental in leading Elijah and Finn to their once home - Mystic Falls - to rescue her, and once there, they had a run in with the reluctant sheriff's deputy; Matt Donovan.|
| ||The Originals, 4x08, Alaric visits New Orleans to give Klaus one of The Hollow's bones, and helps Elijah and Marcel to find the other bones.|
| ||The Originals, 4x13, Hayley got Hope to attend Alaric and Caroline's school of magic. Alaric and Hayley talk about Hope's future.|
| ||The Originals, 5x01, Dorian Williams appeared at the Salvatore Boarding School for the Young & Gifted, while Caroline Forbes visited Klaus.|
| ||The Originals, 5x06, Caroline Forbes met and traveled with Klaus to help him find Hope who ran away with Roman.|
| ||The Originals, 5x07, Caroline's voice can be heard as she narrated her letter to Klaus in which she expressed her condolences for Hayley.||
| ||The Originals, 5x12, Klaus visits Caroline and Alaric at their school of magic to ask Josie and Lizzie to help him with Hope. Elijah and Hope meet Landon.|
| ||The Originals, 5x13, Caroline visited Klaus.|
| ||Legacies, 1x01, Matt appeared.|
| ||Legacies, 1x03, Jeremy appeared.|
| ||Legacies, 1x04, Matt appeared.|
| ||Legacies, 1x06, Josette Laughlin appeared.|