A christian antonio's best friend was another christian bassanio who had fallen in love with lady portia, a rich heiress of belmont. Bassanio being a spendthrift didn't have enough money to show his pomp in the casket ceremony arranged as per portia's dead father's will. Antonio on the other hand was a merchant and had send his valuables foe business in ships to the tripoli, west indies, england etc. so it was decided that antonio and bassanio would go out to see who can lend them the three thousand ducats that bassanio needed. the only person who could help them was the cruel jewish moneylender shylock who hated antonio. for the sake of friendship, antonio decided to sign the bond. THE REST IS KNOWN TO EVERYBODY.