From Athens, Aristotle traveled to Assos, where he was received warmly by the ruler Hermias of Atarneus. Many believe he was acting as an ambassador for Philip of Macedonia, and he was certainly treated as such. He married Pythias, the niece and adopted daughter of Hermias, who was probably about 18 at the time. They had one child, a daughter also called Pythias, but the elder Pythias died about 10 years after their marriage.
Hermias had gathered a group of philosophers on Assos. Aristotle became the leader of this group. Thanks to his father, he was very interested in anatomy and biology and was a great observer. Aristotle and his group began to collect observations while in Assos, in particular in zoology and biology. He also probably began writing Politics during these years as well as On Kingship, which hasn't survive to this day. Unfortunately, politics once again played a part in Aristotles next move. When the Persiand attacked Assos and captured Hermias, Aristotle escaped with many of his scientists to the island of Lesbos. They remained there for about a year, continuing their research.
Return to Macedonia
In 346BC, Philip had created a treaty with Athens. Three years later, after a year on lesbos, Aristotle and his crew arrived in Macedonia, where he remained for seven years. While many would have you believe he taught a young Alexander the great, that story is probably not true. However, it is possible Philip hoped to place Aristotle in charge of the Academy in Athens, since Speusippus was a strong opponent to Philip. If so, he was not able to make this happen.
The treaty between Macedonia and Athens began to crumble in 340BC. When elections were held the following year, after Speusippus's death, Aristotle was not elected. Instead, the position went to Xenocrates. Perhaps because he had lost what he hoped would be his puppet at the Academy, Philip lost his interest in further support of Aristotle. Aristotle moved back to his home in Stagirus along with his circle of philosophers and scientists.
Although he never remarried, Aristotle met a woman in Stagirus named Herpyllis. Exact dates are not clear, but the two had a relationship and a son, whom they named Nicomachus, after Aristotle's father.