Daughter of Ptolemy VIII & Cleopatra III.
Sister of  Ptolemy IX & Ptolemy X.
Cousin & first wife of Antiochus VIII.
Mother of Seleucus VI, Antiochus XI,  Philip I, Demetrius III & Antiochus XII.

Ptolemaic princess who fueled the internecine feud that fragmented the Seleucid dynasty in the late 2nd c. BCE.  In 124 BCE when Cleopatra II returned to Egypt after years of exile in Syria, she married her oldest Ptolemaic granddaughter [Tryphaena] to her oldest Seleucid grandson [Antiochus VIII Grypus].  Years later (114 BCE), when Tryphaena's younger sister [Cleopatra IV] was married to her husband's sibling rival [Antiochus IX], Tryphaena saw her as a threat to her own sons' claim to the Syrian throne.  So she had her sister assassinated at the shrine of Daphne near Antioch (112 BCE). In retaliation, her widowed brother-in-law had her executed, sparking open civil war between her children & her sister's son.

References: Justin, Epitome 39.2-4.

Other resources on line:

• Tryphaena - Christopher Bennett's annotated Egyptian Royal Genealogy provides detailed references to sources.

• Tryphaena - Jona Lendering lists biographical data & chronology of events [Livius: Articles in Ancient History].

• The House of Ptolemy chapter 11 - E. R. Bevan links Tryphaena to the convoluted feud among the offspring of Ptolemy Physcon [archived in Bill Thayer's Lacus Curtius].