The internal space of a N=4 supersymmetric model with Wess-Zumino term has a
connection with totally skew-symmetric torsion and holonomy in \SP(n). We
study the mathematical background of this type of connections. In particular,
we relate it to classical Hermitian geometry construct homogeneous as well as
inhomogeneous examples, characterize it in terms of holomorphic data, develop
its potential theory and reduction theory.Comment: 21 pages, LaTe