A brief history of Athens:- 561 B.C.
How Pisistratus became tyrant of Athens:
In 561 BC Athens found itself being ruled by two tyrants and their parties; Megacles (from the Alcmaeonid family) who's party represented the SeaCoast and Lycurgus who represented the farmers. While they were both trying to undermine each other; Pisistratus came into mind of making a third party.
Pisistratus contrived a devious plan and carried it out. Wounding himself and his mules, and then driving his chariot into the market-place, he professed to have just escaped an attack of his enemies, who had attempted his life as he was on his way into the country. He besought the people to assign him a guard to protect his person. The Athenians, deceived by the story, appointed him a band of citizens to serve under him.
Thus strengthened, Pisistratus broke into revolt and seized the citadel. In this way he acquired the sovereignty of Athens. After a little time Megacles and Lycurgus agreed to forget their differences, and united to drive him out. Thus Pisistratus lost his power, before it could take root.
No sooner had he departed then fighting erupted again between the two main parties. But now Megacles sent a message to Pisistratus, with an offer to re-establish him on the throne if he would marry his daughter, Pisistratus consented. Now Pisistratus and Megacles organised a plan of Hollywood proportions. Pisistratus was to come riding into Athens in a chariot accompanied by a woman named Phya who was to be dressed up as Athena (the goddess). She was to be exclaiming "Citizens of Athens, receive again Pisistratus with friendly minds, Athena, who of all men honors him the most, herself conducts him back to her own citadel."
The plan worked! (lord knows how) and Pisistratus was re-instated his sovereignty, and married according to the agreement, the daughter of Megacles. Pisistratus was already married and it wasn't long before it reached Megacles ears that they hadn't consummated the marriage. Megacles quickly made up with the opposite factions and they ran Pisistratus out of town. Pisistratus was not to be denied, and he started to gather allies both inside and outside Athens. After eleven years, by 542 BC he had a large enough force for him to think that he could retake Athens.
Landing near Marathon he organised his allies to begin a march on Athens. Athens by this time knew he was coming an organised their army to meet him. Pisistratus spurred by an oracle raced out to meet the Athenians after lunch (their siesta time) and routed them. Overtaking the deserters his troops were told to tell each man that he can safely return home. Pisistratus was now the master of Athens a third time. From here he banished many Athenians who he considered against him, to Naxos.
References:
'Histories' by Herodotus published by Wordsworth 1996