The Ptolemy II Philadelphus Eleazar Letters are not an independent work but a set of epistolary documents embedded within the Letter of Aristeas. They purport to be an exchange from the 3rd century BCE between Ptolemy II Philadelphus of Egypt and Eleazar, the Jewish High Priest in Jerusalem. Their literary purpose is to frame the legendary origins of the Septuagint translation.

The correspondence exists solely as a component of the pseudepigraphical Letter of Aristeas to Philocrates. This text presents the letters as authentic diplomatic documents to lend authority to its narrative of the Greek Bible's translation.

The letters are a key literary device within the Letter of Aristeas, a foundational text for the Septuagint legend. They serve to legitimize the translation project by portraying Ptolemy as a pious benefactor and Eleazar as a cooperative authority, thereby asserting the Greek Torah's sanctity for Hellenistic Jews and a wider Greek audience. While fabricated, the correspondence offers valuable insight into 2nd-century BCE Jewish apologetics and ideologies of textual authority in a cross-cultural context.