Patrocles turns up in the current cinematic version of Homer's epic as Achilles' cousin. And only his cousin- which makes it kind of weird that Achilles would be completely heartbroken by his death, and go through all the ritual of deep grieving due to said cousin's death. Implication in the original Iliad suggests that Patrocles is in fact Achilles' bedmate.
Now, much displeasure has been vented on this in various people's LJs, to the tune of: OMFG how dare you write out the fact they were lovers and invent that they were cousins!
I mention 'in various people's LJs' because I've seen this rant a few times now, and unfortunately, there's a flaw in it. See, our 'brilliant' screenplay 'author' did not invent this kinship.
Here's how it works.
RELATIONSHIP NUMBER ONE!
There's a nice chart here, which details the relationships of blood that appear in The Iliad.
Here we find that Achilles was the son of Peleus and Thetis (the couple getting married at the beginning of the Iliad, when Eris pitches in the golden apple and kicks off the whole Trojan war).
We also learn that Achilles's father, Peleus, was the son of Aeacus: his mother and her family are not part of the 'historical record'. Aeacus, however, was the son of Aegina and Actor.
Aegina and Actor had a second son in their household:
Menoetius. Menoetius begat Patrocles.
This makes of Patrocles a relative of Peleus... and thereby, a relative of Achilles.
But there's another aspect to this, too!
RELATIONSHIP NUMBER TWO!
There is also, on the same site, a fairly thorough play-by-play of Patrocles' involvement in things in the Iliad here. Scroll on down this page to the title 'Family', for more information about where Patroclus comes from genetically-speaking. We find that he's Menoetius' son by one of four women.
I can't dig up diddly about the first possible mother's parentage (nor is it offered on the site I'm using as reference).
The second possible mother is a possible link to the Argonauts. As Daddy was an Argonaut himself, this possibility smells quite strong to me. However, as nothing's set in stone, let's look at the other possibilities.
The third possible mother is a descendant of Aeolus, who was Patroclus' great-great-grandfather (Aeolus -> Deion -> Actor -> Menoetius -> Patroclus). Actor apparently had two children in his household: one was Menoetius, who is Zeus' son, but he also begat with Menoetius' mother a child named Aeacus, who begat Peleus, who begat Achilles.
The fourth possible mother for Patroclus is Achilles' half-sister Polymele. Same father as Achilles, but Polymele was begat upon Peleus' first wife, Antigone.
Now, 'cousin' may not be the right word for your mom's halfbrother (I think you'd just call him 'uncle'), but it does suit a fellow grandson of your grandmother.
Now note: I am not saying that Patroclus and Achilles weren't lovers. Chopping that implicitly-stated aspect out of the story is editing, indeed, and pretty damn annoying. But they didn't make up the relations bit: that follows with who both Achilles' and Patroclus' fathers were, and also in two out of three lineage-traceable possible mothers for Patrocles.
You may now freely be pissed off that they're bowdlerizing the lovers bit. Be loud, be extravagantly pissed. But please, for the sake of accuracy, stop bitching they are being described as cousins.
it's possible that they were not intended to be viewed as cousins by the original author (or authors) of the Iliad. It's possible that they were, too. The Truth? Probably not ever gonna be known.
The point I'm trying for here is: they COULD HAVE BEEN cousins, sure- but really, that doesn't give this screenplay's bowdlerizations any more coin.