  Let $(M,Q)$ be a compact, three dimensional manifold of strictly negative
sectional curvature. Let $(\Sigma,P)$ be a compact, orientable surface of
hyperbolic type (i.e. of genus at least two). Let
$\theta:\pi_1(\Sigma,P)\to\pi_1(M,Q)$ be a homomorphism. Generalising a recent
result of Gallo, Kapovich and Marden concerning necessary and sufficient
conditions for the existence of complex projective structures with specified
holonomy to manifolds of non-constant negative curvature, we obtain necessary
conditions on $\theta$ for the existence of a so called $\theta$-equivariant
Plateau problem over $\Sigma$, which is equivalent to the existence of a
strictly convex immersion $i:\Sigma\to M$ which realises $\theta$ (i.e. such
that $\theta=i_*$).
