Now I get where some of this stuff comes from:
https://en.wikipedia.org/wiki/Substitutionary_atonement
"Many but by no means all ancient and modern branches of Christianity embrace substitutionary atonement as the central meaning of Jesus' death on the cross. These branches however have developed different theories of atonement. The
Eastern Orthodox and
Eastern Catholics do not incorporate substitutionary atonement in their doctrine of the cross and resurrection. The
Roman Catholic Church incorporates it into
Aquinas'
satisfaction doctrine rooted in the idea of
penance. Most
EvangelicalProtestants interpret it largely in terms of
penal substitution.
[27]"
" Many of the
Church Fathers, including
Justin Martyr,
Athanasius and
Augustine incorporate a theory of substitutionary atonement into their writings. However, the specific interpretation as to what this suffering for sinners meant differed to some extent. It is widely held that the early Church Fathers, including Athanasius and Augustine, taught that through Christ's vicarious suffering in humanity's place, he overcame and liberated humanity from sin,
death, and the
devil.
[27] Thus, while the idea of substitutionary atonement is present in nearly all atonement theories, the specific idea of
satisfaction and
penal substitution are later developments in the Roman Catholic church and in
Calvinism.
[28]"