Amara is the oldest known ancestor of the Petrova family or bloodline, being born some time during 1st Century B.C.E. (100 B.C.) in Greece. Amara was originally human but became the world's first immortal woman after she consumed the immortality elixir. Amara is assumed to be of Greek origin or descent.
Tatia is the first-known Petrova doppelganger, and her blood was used by Klaus' mother, Esther, to turn her children and husband, Mikaelson, into the first vampires. Following suit is Katherine Pierce, and the modern-day heroine, Elena Gilbert.
It is after she turned immortal that nature try to balance everything by creating the first doppelganger which is Tatia, who would not exist if Amara didn't turn immortal. So Amara is the orginal human with that face and Tatia was the first doppelganger that was created in the image of Amara.
Throughout The Vampire Diaries
In the season four finale of The Vampire Diaries, Graduation, Katherine slept with Niklaus Mikaelson and conceived her daughter, Adyelya.
Adyelya Petrova (Bulgarian: Адиела Петрова), more commonly known as Alice Pierce, is a witch of the Traveler sub-culture and a former main character of The Vampire Diaries. She was also the second-known Petrova doppelgänger of Ismene. In 1490, Alice and her sister were disowned by their father.
Adyelya is a witch-hybrid, having inherited her witch gene from both her mother and her father, the son of Esther Mikaelson. According to Dahlia, as a firstborn of their bloodline, Adyelya has inherited great, but devastating power.
Nadia Petrova (Bulgarian: Надя Петрова) was a major recurring character of The Vampire Diaries. She was a vampire and a member of The Travelers who was Katerina Petrova's daughter, making her an ancestor of Elena Gilbert and a descendant of Amara.
Nadia never mentioned having children, but since Klaus killed Katherine's entire family, there was nobody else to keep the bloodline going except for Nadia's offspring. The series never addressed the plot hole.
Nadia Petrova (Bulgarian: Надя Петрова) is a Vampire and a member of The Travellers. Nadia is also the daughter of Katherine Pierce and Markos. Nadia had spent the last 500 years searching for her mother. She is not very well accustomed to modern American culture and knows about the story of Silas, Amara and Qetsiyah.
Nadia knew Katherine wanted something. Katherine said she wants it all: her daughter, her immortality, and Stefan. "He's my one true love." Katherine decided to stay in Mystic Falls to win back Stefan.
Tatia was a Petrova doppelgänger with whom both Niklaus and Elijah Mikaelson fell in love in the late 10th/early 11th century.
Silas is the second oldest male character in the series universe (after Arcadius who is over 1,000+ years older than him), being 1,000+ years older than the oldest male Original Vampires such as Elijah and Klaus.
Much of Elena's story revolves around her relationships with vampires Stefan Salvatore and his older brother, Damon. It is revealed that Elena is a Petrova Doppelgänger (like Katherine, Amara and Tatia), which is thus responsible for her being identical to her ancestor, Katherine Pierce (née Katerina Petrova).
Amara is the oldest known ancestor of the Petrova family or bloodline, being born some time during 1st Century B.C.E. (100 B.C.) in Greece. Amara was originally human but became the world's first immortal woman after she consumed the immortality elixir. Amara is assumed to be of Greek origin or descent.
Katerina Petrova was born into a somewhat wealthy family in Bulgaria in the late 15th Century. Katerina had a daughter in 1490, however, the two were separated at birth. Katerina became a Vampire in 1492, turned by Rose-Marie's blood.
Esther uses the blood of Tatia, the original Petrova, to feed to her children. This is done because both Klaus and Elijah are in love with her. She also uses Tatia in the curse to bind Klaus's werewolf side from ever surfacing.
Isobel was a member of the Petrova Family and a former relative of the Saltzman Family due to her marriage with Alaric. She was also a relative to the Gilbert Family, as she was Elena's biological mother.
Elena Gilbert (3rd Petrova Doppelgänger): Elena was born on June 22, 1992, in Mystic Falls, Virginia. She was the biological daughter of John Gilbert and Isobel Flemming, and was therefore a descendant of Katerina Petrova, to whom she bears a striking physical resemblance.
The episode starts with a flashback to Bulgaria in 1490 where Katerina (Nina Dobrev) gives birth to a baby girl but her father takes it away immediately because the pregnancy brought shame to the family.
The family relationship between Klaus Mikaelson, Katherine Pierce and their daughter, Adyelya. Klaus and Katherine conceived her in Mystic Falls after Klaus encountered a newly-turned human Katherine in the Mystic Falls Grill.
Known doppelgängers of Silas are Stefan Salvatore and Tom Avery; known doppelgängers of Amara are Tatia, Katerina Petrova, and Elena Gilbert; and known doppelgängers of Ismene are Daria, Adyelya Petrova, and Clara Gilbert.
The Curse of the Sun and the Moon was bound with Petrova blood. And the Petrova doppelganger was created to undo the spell. Thus, Klaus needed Katherine to drain her blood as a sacrifice to break the spell.
At the end of the episode it is revealed why Silas wants Katherine. Katherine's blood is now the Cure since she took it and Silas wants her so he can drain her blood and get rid of the Cure once and for all, while Tessa wants Katherine so that she can take the Cure and kill Silas herself.
Katerina Petrova, also known as Katherine Pierce, was a witch doppelganger of the Traveler sub-culture and became a vampire in 1492.