incidit in scyllam cupiens vitare charybdim

between scylla and charbydis

Percy Bysshe Shelley's returning 
to the idiom in his 1820 essay 

A Defence of Poetry: 

"The rich have become richer,
 and the poor have become poorer;
 and the vessel of the state is driven
 between the Scylla and Charybdis

 of anarchy and despotism."