In the generations gone by (en tais parōichēmenais geneais). Perfect middle participle from paroichomai, to go by, old verb, here alone in the N.T.
Suffered (eiasen). Constative aorist active indicative of eaō (note syllabic augment). Paul here touches God in history as he did just before in creation. God’s hand is on the history of all the nations (Gentile and Jew), only with the Gentiles he withdrew the restraints of his grace in large measure (Act 17:30; Rom 1:24, Rom 1:26, Rom 1:28), judgment enough for their sins.
To walk in their ways (poreuesthai tais hodois autōn). Present middle infinitive, to go on walking, with locative case without en. This philosophy of history does not mean that God was ignorant or unconcerned. He was biding his time in patience.