Creating a strong ally

[Agent Miles]

In my latest GA game, I chose not to conquer any other faction's provinces, except for rebels, unless the province was a GA goal. Something curious happened that may be worth sharing. I was allied to the Sicilians and managed to marry some of my faction’s sons to their daughters over several generations. I then engineered a rebellion on Sicilian controlled Malta with a spy. My army gallantly lifted the ensuing rebel siege of their fort. After this, or perhaps because of it, the Sicilians were loyal allies. I also took steps to aid the Sicilian Crusade on Tripoli by clearing a path for it through Trebizond. After about 150 turns, they have never attacked me at sea or on land. They always chose my side if one of their other allies attacked me. Perhaps there is a lesson to be learned. I am going to try to create one strong ally per campaign, if for no other reason than to have at least one faction as a trading partner when all others are at war with me. Any other tips on what I might do to strengthen an alliance?