In the time of the Mary Queen of Scots, people were confident with their encrypted messages and did not concern the privacy of their messages. However, for some time after that, people started to find a way to create more and more complicated ciphers, for the reason that they realized there are experts who could decipher their messages.

Why people suddenly concerned about this? Because in time of the Mary Queen of Scots, people did not know the existence of cipher experts who could decipher their codes. People were blind overconfident with their encrypted message to hide their secrets. However, there were experts showed out to deciphered their codes suddenly. Their privacy was threatened again and they could not hide their secrets if their ciphers were broken. To deal with this situation, they must create new kinds of ciphers to protect their secrets.

This is actually a phenomenon that cryptography is gradually formed at that time. It generated from some simple ciphers to hide some messages, then some people tried to decode the message and succeeded. To protect their privacy again, people who created ciphers put effort to improve the complicity of their ciphers with their creativity. Then people who decrypted ciphers learn more ways to make sure that they could decrypt more complicated ciphers. A virtuous cycle formed during this process that cipher makers and cryptanalysts improve themselves. Cryptography then improved as well.

The Vigenère cipher is a significant achievement in this process of improvement of cryptography. After hundreds of years of exploring, cipher makers this time created a cipher complicated enough to protect their secrets for a lifetime.