Spy craft goes way back. You can read about it in Herodotus and the Old Testament.
George Washington was a spy master and much of what we think we know about his operations is dot connecting. This is true of most historical accounts of spying.
A good fictional account of true to life spy craft in the 19th century is Rudyard Kipling's Kim. Some of the characters are based on historical persons in the business.
The OG does well to point out the misconception this is somehow a modern invention. It's interesting to read well-researched accounts of spy craft in different historical eras. Its secrecy at the time makes it hard to find source material. They knew how to keep secrets in olden days and there were not many whistle blowers. A lot of what you come across is just speculation. From the article it appears there is quite a lot of source material for Venice.
George Washington was a spy master and much of what we think we know about his operations is dot connecting. This is true of most historical accounts of spying.
A good fictional account of true to life spy craft in the 19th century is Rudyard Kipling's Kim. Some of the characters are based on historical persons in the business.
The OG does well to point out the misconception this is somehow a modern invention. It's interesting to read well-researched accounts of spy craft in different historical eras. Its secrecy at the time makes it hard to find source material. They knew how to keep secrets in olden days and there were not many whistle blowers. A lot of what you come across is just speculation. From the article it appears there is quite a lot of source material for Venice.