The word chronic and the word chronicle haven't shared the same root since before the time of Christ. Chronic ("over a long period of time") traces to the Middle French word chronique, from the Latin word chronicus. This in turn is from the Greek word khronikos, which meant "of or pertaining to time". On the other hand, chronicle ("a written account") is from Anglo-French cronicle, from the Old French word chronique. This latter word differs from the one in the history of chronic semantically; it was a homonym and nothing more. Going farther back, the h was reinserted during Latin chronica, which was a modification of Greek ta khronika, or literally "time book". Here it meets chronic finally under khronikos, which is from the word khronos, which incidentally was the name of the Ancient Greek god of time. After that it's uncertain. It is likewise uncertain that a God created language, but now we know that one of them created at least two words!
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd