Why have calenders been an important tool for so long across many countries?

Because They Help Us To Remember Things Which We Forget Eg:BirthDay,Test,Events Etc-:

americans had many intangible advantages. well since the british fought a war far from home military orders, troops, and supplies sometimes took months to reach their destinations, and the british had an extremely difficult objective. they had to persuade the americans to give up their claims of independence, americans had a grand cause: fighting for their rights, their independence and their liberty. this cause is much more just than waging a war to deny independence.

ask google there you might be able to find an answer for the question you're trying to ask