Under the auspices of the DARPA TIDES project, MITRE, NIST and the LDC began working together to define a new annotation formalism and related infrastructure tools to encourage the interchange of linguistic annotations on a wide variety of "linguistic signals" (text, audio, video, multi-modal signals, etc.). The result was ATLAS, which is an acronym for: Architecture and Tools for Linguistic Analysis Systems.
Of course, Atlas is also one of the gods of ancient Greek mythology. Subsequently NIST developed the jATLAS implementation of the ATLAS formalism, and defined a new type definition language for ATLAS, which they called MAIA. In Greek mythology, Maia is one of the seven daughters of Atlas, or Pleiades.
In keeping with this theme we have named our text annotation tool after another Greek mythological figure, Callisto. Callisto consorted with Zeus (after he tricked her by disguising himself as Artemis). Their tryst resulted in a child, Arcas 1, who came to rule Arcadia later in life. Callisto was punished for being Zeus' lover, and was turned into a bear by Hera. Zeus had pity on Callisto falling to this fate, and so transformed her into the constellation Ursa Major (Great Bear), thus allowing her to gain immortality. He gave their child, Arcas 1, to Hermes' mother, Maia, one of the Pleiades, who raised him to adulthood.