I think you have chapter and verse there, Les.

You can find 17th century versions under the title 'The Sailor's Onely Delight', 18th century printings under 'The Salcombe Seaman's Flaunt to the Proud Pirate' and a 19th century rewrite on broadsides under the title 'Coast of Barbary' which most of the oral versions are based upon.

Someone will be along shortly to tell you it was written by 'ignorant peasants'.