A coherency manager for receiving snoop requests addressed in a physical address space, the snoop requests relating to a cache memory addressable using a virtual address space, the cache memory having a plurality of coherent cachelines, the coherency manager comprising: a reverse translation module configured to maintain a mapping from physical addresses to virtual addresses for each coherent cacheline held in the cache memory; and a snoop processor configured to: receive a snoop request relating to a physical address; in response to the received snoop request, determine whether the physical address is mapped to a virtual address in the reverse translation module; and process the snoop request in dependence on that determination.