The early Days
The Greeks never set out to have an empire. The original Greek, Homer, left his home up in the Caucasus one icy day with the dream of becoming a baseball referee. However his eyesight being terrible he couldn't make a single right call.
The books of Pericles say that he was found stumbling down a mountain screaming "For tha Grreeek Uumpirrre!!" by llama sheppards, who seeing a man stinking with fermented goat wine, sheep crap and facial hair, immediately decided that he was the mouthpiece of the Gods. In fact, only the sheep crap was the Gods' work, as they had left Pan off his leash again.
They immediately started writing down Homer's rambling, which has come to us as Homer's Ale-ad and Homer's Sod-at-sea.
The sheppards became his followers, if only so he would tell them where he found the goat wine, and the Greek Umpire began. Whats the date?
The Trojan War
The following generations kept following Homer's instructions to the letter and in doing so made a killing in selling huge wodden animals. The technique was, you built the giant behemoth and put it in view of the victim, then when the unsuspecting user pulled it in thinking it was free, hordes of salesmen dropped out and made them pay with brutal lock-in, "no-refunds" and you-rolled-it, you-bought-it" policies. Mishaps happened, as in Troy were the Trojans were such bores they didn't bring their animal, a horse, in the town for 10 whole years, by which time the salesmen inside really needed new socks. When they got out they were so angry they made the Trojans buy all sort of added paraphernalia for the horse and then pillaged the city brothels. There was still tales told in Greece of "the Trojan Whore". Historians from the Superior Technology Observatory/New Evidence Division recently clained that the tale was entitled the "Trojan War", but that has been discredited as we all know, S.T.O./N.E.D. scientists are quite unreliable and know nothing. ㅋㅋㅋㅋㅋㅋㅋㅋㅋ
Alexander the Great
As with everything Greek, the legend of Alexander the Great is wrong. In fact, when he was in school everybody called him "Alexander the grate" as he was always throwing hissy fits. One time in fact he ruined a whole period in knot class by slashing the knot in frustration. This forced his father Fillipos to turn to home schooling. This proved a mistake, as his teacher, Opisthobichtes was a firm follower of the Rear Entry doctrine and he soon was giving Alexander regular thrusts of his philosophy. This upset Fillipos quite a bit since it drove him away from the family tradition (Fillipos (filos+ippos friend + horse), was in fact a horse-mounter, a fact corroborated by weird human-equine remains found in his tomb) so he sent the teacher to exile to Rome, and told his son he sent him the other way to throw him off th scent.
Alexander, desperate for his teacher, rode through Greece to raise an army. he was quite unsuccessful until he manage to convince the Greek women that most of their men would in fact not be returning, and promised to bring back nubile nubian non-eunych slaves interested in women instead.
Then he rode ahead towards the Persian Empire, a peaceful state, that was just sitting around waiting for Islam to appear. Its main king, Darius was a major Xena fan, and named his first-born daughter Xena, and then when he discovered that it was in fact a boy, renamed him Xerxes. The king learned of the impending invasion, but was too wrapped up in the Xena scrolls to care. The Greeks plowed through the Persian Empire,every year by Greek fraternities during Spring break in the US. The Persians were in dire need of assistance when a single man arose to defend them. Yomama Bin Slumin was a rich Persian rug manufacturer that rost his wife, children and rectal virginity to the plundering Greek hordes and was bent on revenge. He secretly snuck in Alexander's tent and poisoned his KY jelly with an ointment made from crushed ant bits. This ant thorax ointment (ant th'rax for short) had its desired effect and Alexander died painfully. This didn't stop the Greek hordes that moved on until they reached India, where sources claim they took a wrong turn and ended up in Hawaii. The Persians that remained decided to rename their land the wider Greek empire to prevent any further attacks and when found they out there were a lot of single women waiting in mainland Greece decided to fill the void.
Opinions concur that for there to be a decline, there ought to be a commonly agreed upon rise. Since that is not the case, historians (and herstorians as well) agree that the Greek empire was a mediocre empire from the beginning to the end , when Emperor Diocletus lost the seat of the empire to King Byzantius on a game of Backgammon.