PALAMEDES.  A Greek name that appears in Arthurian legend, and Greek mythology.  It seems to signify a Mede brandishing a weapon.  See Pallas.  And cf. Palladius.
    1)  Greek Mythology.  One of the heroes in the army before Troy.  Though not mentioned by Homer he plays a prominent part in the post-Homeric traditions.  It is generally agreed that he was the son of Nauplius, king of Euboea, and was especially distinguished for quickness of wit and fertility of resource.  He was said to have invented dice and instruments for weighing and measuring. (Heroes and Heroines of Fiction, &c., Walsh, 1915). 
    2)  Arthurian.  This is the name of a Saracen knight, called Palomides in Mort d'Arthur.  He is brother to Saffire whose name is probably Medo-Persian.

    Palamedes (Sir), a Saracen, who adored Isolde the wife of king Mark of Cornwall.  Sir Tristrem also loved the same lady, who was his aunt.  The two "lovers" fought, and sir Palamedes, being overcome, was compelled to turn Christian.  He was baptized, and sir Tristrem stood his sponsor at the font.—Thomas of Erceldoune, called "The Rhymer," Sir Tristrem (thirteenth century). (The Reader's Handbook of Famous Names in Fiction, &c., Brewer, 1899) 

...
Whilst Grecian lance cracks (thundering) Parthian targe,
Parth's flame-flash arrow Grecian through doth prick,
And whilst that Median scymetar unlimbs
The Christian knight, doth Christian battle-axe
Unhead the Median horseman; whilst here dims
The pagan's goggling eyes by Grecian axe,
The Greek unhorsed lies by Persian push,
And both all rageful grapple on the ground;...
—Notes to Southey's Roderic, ii. 237.

(The Cabinet of History:  History of Spain and Portugal, Lardner, v.1, 1832).