53093
In the Royal Navy , the position was introduced in the 17th Century to combat the cost of appointing more admirals - a costly business with a fleet as large as the Royal Navy 's at that time .
 Royal Navy, Royal Navy
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Royal Navy, Royal Navy