Frankinscence , Myrrh, Gold
He was going to force the Graiae(three gray sisters) to tell him the way to the nymphs of the north.
No, he did not. When Perseus met Atlas he had already seen the three sisters and killed Medusa.
The three grey sisters from the perseus mythology are the three sisters that drive a taxi for the immortal people. They help Percy get to Camp Halfblood and the three grey sisters share one eye.
The Sirens were three sea nymphs who lured sailors to their death with a bewitching song.
They were not gods- they were all mortal. All three were mortal, and were considered heroes.
Nereids, daughters of Nereus, are the 50 sea nymphs. Some of these include Amphitrite, the wife of Poseidon and Thetis, the mother of Achilles. Other sea nymphs included the Atlantiades, daughters of Atlas, like Calypso, but the Nereids are the traditional "sea nymphs".
Medusa was the only one of the three sisters that wasn't immortal. She was killed by Perseus.
It was feathered shoes, Bright shield, Helmet of invisibility.
To force them to tell him where Medusa, the gorgon lived.
There are three versions of the Perseus myth and you can find some more information in the attached related links for your covenience.
Medusa was one of the three Gorgons. ( Three women with snake hair and eyes that can turn you to stone.) She was slayed by the hero Perseus.