For thirteen years, Antiochus ruled Tamriel, and proved an able leader despite his moral laxity. Several historians point to proof that Potema cast the spell that ended her brother's life, but evidence one way or another is lost in the sands of time. In any event, both she and her son Uriel were visiting the Imperial court in 3E 112 when Antiochus died, and immediately challenged the rule of his daughter and heir, Kintyra.
But in the same book, it is later said that she died 3 years before him:
Potema died after a month long siege on her castle in the year 3E 137 at the age of 90. While she lived, she had been the Wolf Queen of Solitude, Daughter of the Emperor Pelagius II, Wife of King Mantiarco, Aunt of the Empress Kintyra II, Mother of Emperor Uriel III, and Sister of the Emperors Antiochus and Cephorus. Three years after her death, Antiochus died, and his -- and Potema's -- brother Magnus took the throne.
So who died when?