The Russian Imperial Navy corvette "Bogatyr" made a friendly visit to Melbourne and Sydney in 1863. Information from Polish deserters pointed to Russian plans to attack Australia in support of the Union cause. (See Australia and the American Civil War: Imperial Russian Navy) In 1882 three Russian Navy ships – the "Africa", "Vestnik" (Herald or Messenger) and "Plastun" – made port in Melbourne, sparking renewed fears in the press of a Russian invasion. A brief mobilisation of defence forces ensued before the lack of aggressive intent was made clear. In 1885 concerned British colonists thought a Russian invasion was again imminent and built Bare Island Fort to protect "Sydney's back door" in Botany Bay