Hi,
We would like to know, who Alexander the Great’s siblings were? I searched Google pretty thoroughly I thought, and only found one mention of Cleopatra as his sister. Does anyone know who, Alexander the Great’s other siblings were, if any? Thanks! 
I Alexander the Greats siblings were *Peter the Pretty Good *and Sally the Underachiever.
You forgot Weird Bobby, who used to eat paste.
You might check out information on his father, Philip of Macedon(-ia). Some of his wives / concubines were Audata, Olympias, and Arsinoë. Alexander appears to have had a great number of half- and step-siblings.
The only half-sibling I could recall off the top of my head was Philip Arrhidaeus, who was a bit dim and briefly served as a figurehead monarch.
However as Dr. Drake indicates, after poking around to refresh my memory there were at least a couple of other half- sisters, Cynane and Thessalonike.
The siblings we know about who were important was a mentally retarded half brother named Phillip, who became king of Macedon after Alexander’s death, a sister named Cleopatra, and two half sisters named Cynane and Thessalonike.
You guys are funny … lol… 
Thanks for the serious replies and links also, guys (gals?). We have learned a lot already about Alexander’s family; thanks for helping satisfying my family’s curiosity. Weird questions get thrown around here sometimes. I trust the SDMB to come up with answers to obscure queries. Thx :)
There is a possibility that Ptolemy I of Egypt (one of Alexander’s generals) was Alexander’s bastard half-brother. Given the sexual mores of the day, in fact, there were probably a lot more like that, but he’s the only one I know of off the top of my head.
Mary Renault (an English novelist whose books were published between 1939 and 1981) wrote a fiction trilogy and a non-fiction book about Alexander the Great. She was a pretty meticulous researcher, and most of her books were set in various eras of ancient Greece, starting with the possibly mythical Theseus and ending with Alexander. If you’re curious about or interested in ancient Greece, and want to be educated painlessly, I recommend them.
She also wrote several contemporary novels, but those are not historical in nature. I’ve never read any of those; they’re not my cuppa. If you’re curious about it, check Wikipedia. There is at least one omission I saw on a cursory reading, but maybe I’ll get around to fixing that soon. I’d never looked at that article before.
Ms Renault was only one of many researchers and writers who were at least half convinced that Ptolemy was a bastard son of Philip II. Unfortunately, most of what is assumed was the really good source material has long been lost, and some of the contemporary accounts still extant are extremely biased (Demosthenes, for example).
However, as Ptolemy’s mother was married, it would have been a great shame to both his presumed parents for him to be publicly acknowledged by Philip. I just double-checked the author’s notes in Fire from Heaven (the first book in the trilogy), but didn’t see what I expected. Perhaps it’s in the notes for Funeral Games, but I’m not inclined to stop right now and check all the stuff. It’s all to easy to fall into reading the books; 
Ms Renault was (in mine and many others’ opinions) quite a good writer; her books are still in some demand. Philip is presented as spreading the royal favors around with great, um, generosity.
Certainly, Ptolemy was one of the few people in whom Alexander placed quite a bit of trust - and he was neither a mentor nor a member of the group of youths his own age who were under Aristotle’s tutelage from late childhood. That makes him something of an anomaly. For him to be aware that Ptolemy was a half-sib provides a logical explanation for it. If one looks at busts of the three men, one can discern a (possibly chance) resemblance between Philip and Ptolemy - a far greater one than between Philip and Alexander.
Mary Renault is absolutely the reason I know anything about Ptolemy - I have all her books, they’re totally magnificent. I just like to find a better cite than historical fiction in an online discussion - even well-researched historical fiction. 
I don’t see any mention of Ptolemy in the Author’s notes of The Persian Boy or Funeral Games either (I did, however, get to re-read her savaging of Curtius, which is always fun). And I don’t know how much of her portrayal of King Phillip as a root-rat is necessarily shared by other historians or just her opinion (which, as she openly acknowledges, is often different from the scholarly consensus of her day)
Actually Peter Green indicates he was part of Aristotle’s group at Mieza and Robin Lane Fox at least alludes that he was. Green also mentions the rumour of him being one of Phlip’s bastards. Even if a little older, he does seem to have been associated with Alexander from a young age and he was in the group of Alexander’s associates banished by Philip in the wake of the Pixodarus affair in 336. He may have been favored as a half-brother, but I wouldn’t set him apart as being all that distinct from Alexander’s peer group.
But count me as another Renault fan ;). Personally Funeral Games was my favorite.
So was the latter named for the city, or the other way around?
Other way around. Cassander, Alexander’s bitter rival and Thessalonike’s husband ( after Alexander’s death ), founded the city and named it after her.
Very interesting. I’ve been to Thess, but never looked up any facts about the place.
Alas, with the exception of a very few individuals, there’s insufficient source material on most of the prominent people of that era. I took a 3-course series (grad/undergrad level) on Hellenic, Hellenistic, and late Roman Republic history in college from one of the most gifted lecturers it has ever been my pleasure to hear.
For too many important people, there really isn’t much beyond Plutarch’s Lives, or Herodotus, or the surviving works of one of the philosophers - not what you’d call unbiased sources, really - even those who tried, as Herodotus apparently did some of the time.
So the writers do their research, and reach their conclusions - whether they’re writing fiction or (putative) non-fiction. It all involves an enormous amount of guesswork, along with tedious and painstaking hard work (if done right). Quite naturally, each of them reaches his/her own conclusions. We could play “pick your expert” for weeks, and still wouldn’t know any more than we do (at least, we who have even tried to learn about it).
It would be nice to have a time machine, or perhaps, to have the system Asimov hypothesized in one isolated short story, where everybody had the capability to trace back through all their ancestral lives and directly see/experience what they knew and what they did. Sorry, can’t recall the title. I think I read it while he was still alive. Maybe in Isaac Asimov’s Science Fiction Magazine?