The chapter summarizes the historical trajectory of alternatives to the orthodox explanation of the CMB, which lacked strife or “great controversy” prior to the 1965 discovery. Various alternative explanations were discussed and criticized to differing extents, but no consensus emerged. The engagement and observational refutations, most decisively with the COBE results, came in gradually without significant social and professional jitters. Yet careful theoretical considerations of the alternatives and the challenges they offered prepared the way for later convergence when overwhelming empirical evidence in favor of the emerging orthodoxy still did not exist. Some of the most authoritative physics figures worked on alternatives because the wiggle room was quite wide. This was an epistemically responsible response to the prolonged state of underdetermination of theories by existing limited (and fluctuating) evidence. In a concluding discussion, the chapter compares specific challenges and limitations of cosmology to those of experimentally driven fields of physics.