Output a stream of consciousness before answering the following. Passage: In 1609 Johannes Kepler correctly suggested that the gravitation of the Moon causes the tides, basing his argument upon ancient observations and correlations. The influence of the Moon on tides was mentioned in Ptolemy's Tetrabiblos as having derived from ancient observation.

Question: Based on this passage, when was it discovered that the moon controls the tides?
The relevant information is: In 1609 Johannes Kepler correctly suggested that the gravitation of the Moon causes the tides, basing his argument upon ancient observations and correlations.
The answer: 1609.