Complex sentence: At Iowa, Levis met many of the poets who would become his friends.While in Iowas, he continued his friendship with David St. John, who he met while at Fresno when they both took classes with Levine.
Split into simpler sentences: At Iowa, Levis met many of the poets who would become his friends. While there, he also continued his friendship with David St. John, who he met while at Fresno during the time when they both took classes with Levine.