  We investigate multi-flavour gauge theories confined in $d\es 2n$-dimensional
Euclidean bags. The boundary conditions for the 'quarks' break the axial
flavour symmetry and depend on a parameter $\theta$. We determine the
$\theta$-dependence of the fermionic correlators and determinants and find that
a $CP$-breaking $\theta$-term is generated dynamically. As an application we
calculate the chiral condensate in multi-flavour $QED_2$ and the abelian
projection of $QCD_2$. In the second model a condensate is generated in the
limit where the number of colours, $N_c$, tends to infinity. We prove that the
condensate in $QCD_2$ decreases with increasing bag radius $R$ at least as
$\sim R^{-1/N_cN_f}$. Finally we determine the correlators of mesonic currents
in $QCD_2$.
