Selim I wanted to use the Ottoman Empire’s central location to completely cut the ties between Shah Ismail’s Safavid Empire and the rest of the world.
Shah Ismail received revenue via customs duties, therefore after the war to demonstrate his commitment to their thorny rivalry, Selim I halted trade with the Safavids[61]—even at the expense of his empire’s own silk industry and citizens.
Must have been a bad breakup:
https://en.wikipedia.org/wiki/Selim_I