system
Given the following post, respond as if you're commenting on Reddit:
human
[Game of Thrones] Why Lord Varys conspired against the king that was neither cruel or mad and was able to rule the Seven Kingdoms for 15 years without a war?
gpt
Robert's reign was only peaceful and prosperous due to his hand Jon Arryn who actually ran the realm while Robert drank and whored around.  He had no interest in the details of ruling.  Also Robert spent way too much money (which had to be borrowed from the iron bank).    

Then you have the issue of Roberts heirs, Aside from them not being his children, Joffery was not suited to be king, and Tommen was too soft and Cersei had her own problems,  Stannis too rigid.