Wanda Maximoff and her twin brother Pietro were born the children of Natalya Maximoff. Natalya was a Romany woman, well versed in witchcraft as the Scarlet Witch, a mantle and talent she inherited from her father. Natalya was a force for good in eastern Europe as she traveled, using her magic to battle demons and the unseen. She became pregnant by an unknown but apparently dangerous man, giving birth to her twins. While traveling for her work, Natalya left the infants with her brother Django and his wife Marya to care for.

The High Evolutionary, a reclusive geneticist from Wundagore Mountain in Transia, was searching the countryside for special children  to use as test subjects in his experiments. A cowardly priest in nearby Serbia had heard of the birth of Natalya’s children and directed the Evolutionary and his New Men towards the Romany to spare his own people. The Evolutionary extracted the twins from the Maximoffs and brought them back to Wundagore. His experiments modified their genetic structure, hoping to create specific outcomes for his work. Meanwhile, Natalya had come to Wundagore in search of her children. Tales tell of a battle between the Scarlet Witch and the Knights of Wundagore on that mountain, but Natalya’s own ghost said it was actually the twins’ father who was responsible for her death. Having altered the children but unsatisfied with the final product, the High Evolutionary made further genetic modifications so that the twins would register as common mutants in order to hide his involvement. Apparently touched by Natalya’s courage, the Evolutionary chose to return the twins to the Maximoffs rather than abandoning them entirely.  [Uncanny Avengers (2nd series) #5, Scarlet Witch (2nd series) #11-14]

Other parties were present at Wundagore around the same time. Some tales report of a woman named Magda, pregnant and fleeing from her dangerous husband, who took shelter among the New Men. Magda reportedly gave birth before disappearing into the wintery storms, never to be seen again. [Avengers (1st series) #186, Classic X-Men #12, Vision and the Scarlet Witch (1st series) #4] An American couple named Bob and Madelyne Frank had also arrived while pregnant. Formerly the Invaders known as Whizzer and Miss America, the Franks had been exposed to radiation which made their first child hazardous at birth. They sought out the Evolutionary for aid with their second pregnancy, but Madelyne and her child still died in childbirth. The Evolutionary’s midwife Bova attempted to pass Wanda and Pietro off on the grieving Bob Frank, but he was crushed by his wife’s death and abandoned his alleged children on Wundagore. [Giant-Size Avengers #1] Though the High Evolutionary eventually returned the twins to Django and Marya, these complications would lead to confusion about Wanda and Pietro’s true parentage for many years to come.

[Note: The complications involving Wanda, Pietro and their 3-4 different sets of parents is legendary by this point. As of this writing, there is no concrete evidence Magda was EVER on Wundagore or even pregnant, given the number of lies told by the Evolutionary and his agent, Bova. Putting aside who believed what and when and why, the current retcons mostly hold. Sliding timeline issues make it hard to believe two couples of World War II survivors (the Franks, plus Magnus and Magda) could believe their missing children were these twins born between 25-30 years ago, but that’s Marvel-Time for you. The only other concern is Wanda’s lifelong connection to Chthon was supposedly because she was born on Wundagore during his manifestation fighting against the Knights. Current stories claim she was born first and then brought to Wundagore afterwards for the Evolutionary’s experiments. No one has explicitly said she wasn’t born on Wundagore at an earlier point, though, which is possible given Natalya’s traveling nature.]

At a young age, Wanda's vast potential for wielding magic was detected by those skilled in the art, and she was approached by the most powerful coven in her Eastern European homeland: Margali Szardos, Maria Russoff and Lilia Calderu. Lilia sent out a summons through the Romany for Marya Maximoff to bring Wanda to her caravan, and then the witch brought the young girl to Castle Russoff to meet her fellow sorceresses. Her initiation would not go uncontested, however - a servant of Chthon known as Taboo learned of the coven's attempt to indoctrinate Wanda and, more importantly, that Lilia was in possession of the Serpent Crown of Set. His master Chthon had gone to great lengths to prepare the girl Wanda for his own future uses, and he would lose the child to his brother Elder Demon, Set, if the witches brought her into the coven under the influence of the Crown. Therefore, Taboo and his associate Damballah interrupted the coven's ceremony with Wanda. The conflict only ended when Wanda manifested her hex power for the first time, inadvertently giving Chthon himself a chance to reach out to the material plane. He nonchalantly disposed of the Serpent Crown and decreed that Wanda would join no coven, under penalty of his wrath. The witches assented, and returned Wanda to her family to grow without tutelage in magic. [Mystic Arcana - Scarlet Witch]

Wanda and Pietro were raised by Django and Marya as their own, and believed the Maximoffs to be their biological parents. As the Maximoff’s were well accepted within the Romany community, nothing seemed to change  at first when the twins began to develop "mutant" abilities as teenagers. However, the need to feed his family forced Django to steal, which led to some angry villagers chasing him and burning down the entire camp. When Marya seemingly perished within the flames, Pietro and Wanda would flee, believing their father and brethren would be killed by the mob as well. The shock of seeing everything they held dear go down in flames was too much and it would be years before either of them could fully recall those days. [all from Avengers (1st series) #185-186, 234, Giant-Size Avengers #1, Uncanny X-Men Annual #12, Web of Spider-Man Annual #4]

Pietro only remembered that his father had told him always to watch over his sister and he did as best he could. Over the next few years, they took whatever shelter they could and Pietro used his speed to catch them some rabbits as food. At one point, they were sought out by Charles Xavier, who offered them special training at his school in America, but Pietro refused, thinking that they could master their powers on their own. One fateful day, Wanda strolled into a nearby village and, by accident, she caused a barn to catch fire with one of her unpredictable hexes. She was thought to be a witch and would have been burned at the stake had it not been for the Magneto, who rescued her from the mob. [Professor Xavier and the X-Men #4, Avengers (1st series) #234, X-Men (1st series) #4]

Magneto brought Pietro and Wanda to live with him on Asteroid M, his orbital base, and began training the young mutants as part of his Brotherhood of Evil Mutants, christening them Quicksilver and the Scarlet Witch.  The twins only stayed because they were indebted to him, as Magneto had saved Wanda's life, and were forced into performing many terrorist actions they despised taking part in. Both Mastermind and the Toad of the Brotherhood took an unhealthy interest in Wanda, but time and again Pietro protected her from them. (Magneto also kept his henchmen in line, from time-to-time, but only to assert his own authority.) Several times, the Brotherhood opposed the X-Men when both groups tried to recruit some thus-far unknown mutants. Wanda and her brother were finally freed when Magneto was carried off to another world by the enigmatic Stranger. Although they were once more offered the chance to join the X-Men, the siblings decided to take some time for themselves and returned to Transia. [X-Men (1st series) #4-7, 11]

Shortly thereafter, Pietro saw a newspaper article proclaiming the Avengers were looking for new members and he convinced Wanda they should audition for the group. The twins connected with the Avengers' patron, Tony Stark, to secure their immigration status and background checks. The Avengers' government liaison Agent Murch was racist and confrontational with Wanda and Pietro, but Stark was happy to throw him out of the room and assured the twins of a smooth transition. [Avengers: Earth's Mightiest Heroes #7-8] They succeeded in the recruitment and were inducted into the Avengers as replacements for Giant-Man and the Wasp. Pietro and Wanda were, along with Hawkeye, the first reformed villains to be accepted into the group. Led by Captain America, this incarnation of the Avengers was referred to as "Cap's Kooky Quartet" and was the first major upheaval of the Avengers roster in history. [Avengers (1st series) #16] The early days of the group were filled with in-fighting, especially with clashing hot-heads Quicksilver and Hawkeye. Furthermore, Hawkeye was openly flirtatious with Wanda (more often than not to annoy Pietro), but Wanda privately had stars in her eyes for the Star-Spangled Avenger. Still, they soon evolved into one of the most tight-knit teams of Avengers to date. What they lacked in power, they made up for with teamwork.

At one point in their membership, Wanda and Pietro took a leave of absence to return to Wundagore, as they both felt their powers fading. Apparently, some strange element in their native area revitalized their powers, though the diathermic treatments of a local scientist too had some influence in their recovery. [Avengers (1st series) #32] Almost back at full strength, Wanda and Pietro once more were contacted by the X-Men, who needed more firepower against the imminent threat of Factor Three. However, like before, the twins refused, reasoning that, if they returned to the States, it would be as Avengers. [X-Men (1st series) #27]

Just when they were about to return to America, an alien craft landed in Transia and the aliens captured the two mutants. Ixar, a shapeshifter, then journeyed to Avengers Mansion, posing as Wanda, and lured the heroes into the craft as well. Despite Captain America suspecting a trap, the Avengers were nearly overpowered but, in the end, they managed to drive the aliens away from Earth. [Avengers (1st series) #36-37] Quicksilver and the Scarlet Witch officially rejoined the ever-changing roster of Avengers, including new and returning allies, like Goliath, the Wasp and Hercules. Hawkeye had returned to his relationship with the former spy, Black Widow, but the beautiful Wanda caught the attention of Hercules, much to the jealous ire of their reoccurring foe, the Asgardian Enchantress.

Pietro, however, was slowly developing a resentment towards humanity, like Magneto. This gnawing doubt sprang up full force when Magneto returned from space, captured the twins and asked them to accompany him to the United Nations, where he instigated an assault on the Scarlet Witch by one of the security guards. Enraged at his sister's injury, the culprit being a “mere human”, Quicksilver rejoined Magneto's Brotherhood and brought the unconscious Wanda along with him. [Avengers (1st series) #46, 48-49]

Her forehead being scratched by a bullet, Wanda again temporarily lost the use of her powers and could do nothing to intervene with Magneto’s schemes to capture the X-Men and force them into his service, save argue with her brother. After calming down, Pietro soon realized how rash his actions were and, with the help of the Avengers, the X-Men and Magneto's flunky, Toad, the Master of Magnetism was apparently killed in a landslide. Instead of returning to the Avengers, Wanda, Pietro and Toad became traveling companions, looking for a peaceful existence somewhere in the world. [X-Men (1st series) #45, Avengers (1st series) #53]

It didn't work. Soon, they were captured by the Sentinels, like most other known mutants at the time, and again they had to rely on the X-Men to bail them out. After being freed from the Sentinel base, the Toad once more opted to travel with the twins, still having his crush on Wanda. [X-Men (1st series) #59-60]