  We study compactification of 6 dimensional (1,0) theories on T^2. We use
geometric engineering of these theories via F-theory and employ mirror symmetry
technology to solve for the effective 4d N=2 geometry for a large number of the
(1,0) theories including those associated with conformal matter. Using this we
show that for a given 6d theory we can obtain many inequivalent 4d N=2 SCFTs.
Some of these respect the global symmetries of the 6d theory while others
exhibit SL(2,Z) duality symmetry inherited from global diffeomorphisms of the
T^2. This construction also explains the 6d origin of moduli space of 4d affine
ADE quiver theories as flat ADE connections on T^2. Among the resulting 4d N=2
CFTs we find theories whose vacuum geometry is captured by an LG theory (as
opposed to a curve or a local CY geometry). We obtain arbitrary genus curves of
class S with punctures from toroidal compactification of (1,0) SCFTs where the
curve of the class S theory emerges through mirror symmetry. We also show that
toroidal compactification of the little string version of these theories can
lead to class S theories with no punctures on arbitrary genus Riemann surface.
