Myth #1: Arminian theology is the opposite of Calvinist/Reformed theology. This is not true: Arminius and most of his followers are part of the broad Reformation movement and there is common ground.
So, Roger Olson, Arminian Theology, chp. 1. Do you see Arminian theology as a development of the Reformation or as a departure from the Reformation?
First, Olson makes a case — knowing some disagree — that Arminius was part of the Dutch Reforming movement and that he was trying to correct Calvinism from unbiblical ideas. He was against a strict, or radical, monergism. He was, according to some Calvinists, a left-wing Calvinist.
Second, there are two major links: both Arminians and Calvinists are united on an emphasis on God’s glory and on covenant, or federal, theology. (If this surprises you, you need to read this book; I can’t give all the details here.) And there is a major connection between the two with the doctrine of prevenient grace: all good comes to us through grace, even saving faith. Both believe in total depravity: mind, heart, and will.
Third, Wesley said he and his followers were close to Calvinism in ascribing all good to the free grace of God, in denying all natural free will and all powers antecedent to grace, and in excluding all merit from humans.
Fourth, there are real differences — unbridgeable differences. But the big point is that these two systems are not opposites, they are not mirror images of the other.