  We study the dynamics of entanglement between two spins which is created by
the coupling to a common thermal reservoir. The reservoir is a
spin-$\frac{1}{2}$ Ising transverse field chain thermally excited, the two
defect spins couple to two spins of the chain which can be at a macroscopic
distance. In the weak-coupling and low-temperature limit the spin chain is
mapped onto a bath of linearly interacting oscillators using the
Holstein-Primakoff transformation. We analyse the time evolution of the density
matrix of the two defect spins for transient times and deduce the entanglement
which is generated by the common reservoir. We discuss several scenarios for
different initial states of the two spins and for varying distances.
