Alicent Hightower was the daughter of Otto Hightower, Hand of the King under Viserys I, and by most accounts spent her girlhood at court as companion to the king's own daughter Rhaenyra before becoming, at her father's careful arranging, the king's second wife after Queen Aemma's death. The friendship between the two women did not survive the marriage; the rivalry that replaced it outlived them both.
She gave Viserys four children — Aegon, Helaena, Aemond, and Daeron — and spent the rest of the reign convinced, with reason the record does not entirely dismiss, that her son's claim to the throne was being quietly buried under his half-sister Rhaenyra's. When Viserys died in 129 AC, it was Alicent's faction that crowned Aegon II before Rhaenyra could be summoned, and it was that crowning, more than any single act of Alicent's own, that lit the war the Citadel calls the Dance of the Dragons.
She survived the war her son's coronation began, which is more than most of her children managed. Confined during the worst of the fighting and held under guard afterward on suspicion of working against the peace, she died in 133 AC during an outbreak the smallfolk called the Winter Fever — one of the plainer deaths in a family history otherwise crowded with dragonfire and murder.