I'm looking for the answer of who first proved modularity of CM curves?  That is if $E$ is an elliptic curve over $\mathbb{Q}$ which has complex multiplication then there's a non-constant morphism from $X_0(N)$ to $E$ for some $N$ (not necessarily the conductor).  The possible names that I've thought of are Hecke, Deuring, Weil or Shimura.  Does anybody know something more definite?