The fresco fragment known as the Lady of Mycenae was found in the Cult House below the palace of Mycenae. She is a rather stolid older lady, with ample arms and a sagging chin, offering necklaces to a deity.
In 1951, workers renovating the so-called Tomb of Clytemnestra at Mycenae discovered a cemetery that is now known as Grave Circle B. The burials were excavated between 1952-1954.
Thirty-six years later, in 1987, British forensic reconstruction specialists John Prag and Richard Naeve were asked to give faces to some of the human remains. Initially, they were asked to put faces to the skulls found by Heinrich Schliemann in Grave Circle A, hopefully to provide a glimpse of the men behind the 'Mask of Agamemnon' and the other death masks. Unfortunately, due to the high alkaline content in the soil around Mycenae, and the haphazard archaeological techniques of Schliemann's day, not enough material remained to attempt a reconstruction.
The remains in Grave Circle B had fared slightly better, partly due to more advanced and careful archaeological practices. Prag and Naeve reconstructed several faces, all male, with the exception of one woman whose skull was intact enough for the procedure. Technically, she is known as Gamma 58, but the forensic team dubbed her 'Clytemnestra,' after the most famous woman of the Atreid ruling dynasty, even though she would have lived 300 years before a real-life Clytemnestra. Her pathology indicated she was around 35 at the time of death, tall and strongly built, though slender. She showed arthritis in the lower back as well as in her hands. It isn't clear how she died, or whether she had any children.
During the reconstruction, the forensic team noticed similarities between her heart-shaped features and those of her fellow grave occupant, a young man known as Gamma 55; they speculated there might be a blood relationship between the two. Later DNA analysis confirmed that Gamma 55 and 58 were, indeed, brother and sister. So she's really more of an 'Elektra' than a 'Clytemnestra.'