A tangled though remarkable story behind the proof in the mid-1950s of the existence of a competitive general equilibrium (Arrow-Debreu, as it is known) is summarised in a recent posting on economicprincipals and revised (rather drastically, it must be said) here (scroll down to ‘A correction’).
There are strong echoes of the controversy over the proper academic credit for the discovery of the double helix structure of DNA. In the Economics case, the problem was compounded by a very slow refereeing process while rivals worked on a related research paper.
Economic Principals is itself an interesting website reporting on topical issues as well as presenting non-technical interpretative overviews of controversies in economics, often disentangling the intellectual, institutional and personal issues. One example, amongst many, relating to the 2011 Sargent-Sims Nobel Prize, is here. The full archive is online.