Answer: Tense and Clever
Step-by-step explanation:
The Adams-Onis Treaty is known as an agreement between Spain and the United States that settled border disputes between those two countries. It was signed in 1819.
As two adjectives that can describe this kind of agreement that had huge key in our history I will use: Tense and Clever
You can also use adjectives such as: Enormous, Great, Adventurous, Graceful, Alive and more.
As descriptive phrases you can use: effective, circumstantial and more.