In Strasbourg, my husband and I became ecclesiastical two-timers. Once we'd done that, it was easy to become three-timers.
Jill Gill has produced a remarkable account of the declining influence of mainline Protestantism and the NCC in the 1960s and 70s.
The broken communion evident at any eucharistic service is an outward and visible sign of an inward and invisible state of affairs.
The Vietnam War forced Protestant ethicists to consider Catholic teachings about war, and I learned much from Catholic colleagues. My outlook was also changed by ecumenical contacts of another kind.