  Various results on factorisations of complete graphs into circulant graphs
and on 2-factorisations of these circulant graphs are proved. As a consequence,
a number of new results on the Oberwolfach Problem are obtained. For example, a
complete solution to the Oberwolfach Problem is given for every 2-regular graph
of order 2p where p = 5 (mod 8) is prime.
