Tryphaena was the daughter of Cleopatra III and Ptolemy VIII Physcon. She was born during their reign with Cleopatra II and married Antiochos VIII Grypus at around the same time the three of them reconciled in 124. The Seleukids had been dealing with their own internal strife with several different men claiming the throne. Tryphaena’s marriage brought Egyptian political support and troops in to support her new husband Grypus. Her resources swung things in his favor and soon he was king, with her as queen. The couple went on to have probably five sons and one daughter.
In 115, things changed. Her sister, Cleopatra IV, was divorced from her husband, Ptolemy IX Soter, on the orders of their mother. Rather than pursue queenship in Egypt once more, she raised an army and offered her own hand in marriage to Antiochos IX Cyzicenus, Grypus’ half-brother, cousin, and rival for the throne. Tryhpaena was furious. She accused her sister of bringing a foreign army into a dispute between brothers and of marrying outside of Egypt without their mother’s permission. Three years later, she saw her chance. When Cleopatra took refuge in a temple, Tryphaena ordered her executed there, despite people’s warnings about angering the gods by such an act.
Tryphaena herself would not live long after this. Her brother-in-law captured her less than a year later and had her executed. Her sister Selene eventually married Grypus herself.
Justin, Epitome of the Philippic History of Pompeius Trogus 39.2-3 - Forumromanum.org
Flavius Josephus, Antiquities of the Jews 13.13.4 - Perseus
Tryphaena - Egyptian Royal Genealogy
Tryphaena - Livius.org