Elizabeth Warleggan (formerly Poldark, née Chynoweth) was the Mistress of Trenwith and the wife of the late Francis Poldark, with whom she had one child, Geoffrey Charles Poldark. She was widowed and later became the wife of George Warleggan. She had her second child, Valentine Warleggan, but his true paternity is unknown.
At some point, she met and became engaged to Ross Poldark. In 1780, Ross was arrested for brawling and joined the British Army. By 1783, he was presumed to have died. She fell in love with Francis Poldark and they became engaged.
A couple of weeks before her wedding to Francis, she attended a meal in Trenwith. She was shocked when Ross Poldark returned home and felt awkward when they had to tell him about their engagement.
Elizabeth thought about leaving to speak with Ross, but her mother persuaded her to stay. She eventually decided to stay engaged to Francis, and they were married. They had a child, Geoffrey Charles Poldark, the following year.
Elizabeth loved her son very much, and cared for him. They were very close. They survived a sickness when they were cared for by Demelza Poldark. Demelza had married Ross, something which Elizabeth was shocked about because he married below his status.
Francis remained insecure about his marriage, because he knew of her former love for Ross. He gambled and their marriage suffered. Elizabeth was delighted when Francis started to improve, and invested in a new mine, Wheal Leisure, with Ross. She was devastated when Francis died.
Elizabeth and her remaining family struggled when her husband died, because they no longer had the wealth they once had. Her mother had a stroke, and Elizabeth struggled to provide proper care for her. The home was freezing and they were struggling to buy food. Ross Poldark sold his shares in Wheal Leisure and gave her the money, but it was not enough. When George Warleggan, the wealthy banker, found out about her situation, he agreed to help her pay for her mother's care and to keep Trenwith.
However, he had hoped Elizabeth would agree to marry him in return. Elizabeth thought she had no choice but to agree to the proposal, in the hope of improving the future of her son. She accepted his proposal, but when Ross found out, he was unhappy. Elizabeth had tried to spend more time with Ross since her husband died, and their unresolved feelings reached breaking point. They spent the night together, but Ross regretted his choice and departed early the next day.
Elizabeth had thought there was a chance that Ross would leave Demelza and reunite with her. However, he later made his choice to stay with Demelza.
Elizabeth later married George less than a month later, and she found out she was expecting her second child. She already knew the paternity of her child was in doubt, and she and Agatha thought it likely that the father was Ross. However, Elizabeth knew she had to stay with George, and told him she was pregnant with his child, to his joy.
By the time her child was born, things had changed for her family. Ross and Demelza no longer visited them and kept their distance, to the disappointment of her son and Agatha. George was strict and cold toward her son, and was open with his lack of care for Agatha. He and Elizabeth preferred to keep their distance from Ross and she often felt like she had to agree with what George wanted.
Elizabeth was unhappy when George brought her cousin, Morwenna Chynoweth, to Trenwith to teach and care for Geoffrey Charles, without asking her. George told her that she needed to distance herself from her elder son, because he thought they should send him to boarding school the next year. Elizabeth had wanted to keep him with her, but George had the final word, telling her that she would have their child to care for soon.
Elizabeth had given her support for the idea of changing Geoffrey Charles surname from Poldark to Warleggan, but she remained quiet when he refused. At the time, Elizabeth's pregnancy was at least in her eight month. However, she knew there was a chance she was nine months pregnant, and that her child would be born early in the eyes of George.
Elizabeth began to find ways to claim her labour had started early, and took to undertaking tasks that could induce labour. George had tried to make Elizabeth rest, but she staged a fall when he went out for the day. It is unknown whether she truly did fall, or whether she said she had when she went into labour, but she gave birth to her second son, Valentine Warleggan, following a long and worrying labour.
She managed to convince everyone that Valentine was simply born early, and George was delighted to have a son. However, Elizabeth struggled in light of her child's birth. She was quite cold toward him, and knew that he looked like Ross, even though George thought Valentine looked like him. She was upset when Geoffrey Charles said he and his brother looked very unalike, and to find out that he was sneaking out the house to meet with Ross.
Elizabeth became very unhappy, and was sad at the news that Ross and Demelza had another child, a daughter. She and her son later moved with George to Warleggan House.