Rome, a city of thieves and bandits, had a problem of declining birthrate for the lack of women.
The senate suggested the city sponsor a regional festival, inviting the neighboring cities to gather outside its walls and join the celebration.
    It was a trap.
    The men of Rome suddenly swooped out and abducted enough women to ensure a steady birthrate, and dragged them inside the city’s walls.
    When negotiations for the return of the women failed, one by one the cities declared war on Rome. Each were defeated except the Sabines.
    The Sabines marched on Rome and the siege continued until a Vestal Virgin, Tarpeia, betrayed Rome and opened the gates to the Sabine army.
    It did not end well, the Sabines were expelled and Tarpeia was flung from the eighty-foot high cliff that still bears her name, The Tarpeian Cliff.
    Rome was surrounded by potentially hostile tribes and needed allies. When the Celts began a migration south from the Alps, the Etruscians asked Rome for military aid.
    Rome sent an army of 10,000. The Celts sent 30,000. It did not end well for Rome. The Celts followed the retreating Roman army. Buildings were burned or plundered, and most of the Roman senate was put to the sword at the Forum.
    The surviving Romans fortified themselves atop the Capitoline Hill repelling several Celtic attacks. The Celts left the city only after the Senate agreed to pay one thousand pounds of gold.
    After the Celts were gone their neighbors thought Rome weak and tested their resolve. 
Romans were victorious and rebuilt, but they never forgot.
    Rome learned to never trust its neighbors. Driven by the fear that the neighbors would plot against them, Rome surrounded itself with trusted allies, whether they liked it or not.