"Compelling Men to Mourn".
Sister of Hippolyta and Antiope, Penthesilea was another queen of the Amazons. In yet another story revealing the death of Hippolyta, it was said that Penthesilea had killed Hippolyta in a hunting accident and was so distraught over her actions that she decided to kill herself. However Amazon custom decreed that she had to do it honorably and so she joined the already waging Trojan War, fighting on the side of Troy.
She arrived with twelve companions (one of them was Antandre, her name meaning "Preceding Men", another was Antibrote and Bremusa, whose name means "Raging Female". She was killed by Idomeneus, who wounded her in the breast.) and promised the Trojans that she would kill Achilles for killing Hector. On her first (and last) day of fighting, she fought against Ajax, then moved on to Achilles. Overpowering her too easily, Achilles pins her to the ground, ignoring her pleas for mercy and kills her. When he removes her helmet, he is so smitten with her beauty that he mourns her death. When fellow soldier Thersites made fun of him for his show of weakness, he killed him.
In an interpretation of the story by 12th century Byzantine scholar Eustathius of Thessalonica, he argues that Archilles grief was so great, that he performs an act of necrophila on Penthesilea's body. Considering the erotic nature of many Greek myths, this may not seem so far fetched.