They created the number system and discovered that the earth was round by studying eclipses.
Hope this helps.
A group of members invited William of Orange to "invade" England.
Answer:
John Locke wrote a famous work called An Essay Concerning Human Understanding (1689), where he showed his theory of ideas and his account of the origins of human knowledge in experience. he also wrote Two Treatises of Government (first edition published in 1690 but substantially composed before 1683).
In this context alliance would mean to come to a formal agreement to help each other.