  We define a method for edge coloring signed graphs and what it means for such
a coloring to be proper. Our method has many desirable properties: it
specializes to the usual notion of edge coloring when the signed graph is
all-negative, it has a natural definition in terms of vertex coloring of a line
graph, and the minimum number of colors required for a proper coloring of a
signed simple graph is bounded above by {\Delta} + 1 in parallel with Vizing's
Theorem. In fact, Vizing's Theorem is a special case of the more difficult
theorem concerning signed graphs.
