Holy Roman Empire
British Empire
Northwest Territory
Queen’s County.
b. When it is used with the preposition of in such phrases as Borough of the Bronx, Department of the Gulf.
c. When part of a nickname, The Crescent City, the Buckeye State, the City of Brotherly Love.
Be careful not to capitalize such words when they are not an actual part of the name. French Republic is the name of the county, exactly translating Republique Francaise, but American republic is not such a name. You would write State of New York in a legal document in which the state would be considered as a corporate person, but in ordinary references it would be state of New York.
17. The days of the week and the months of the year, but not the seasons unless personified.
Monday the fifth of August.
April is the first month of spring.
Spring, beautiful Spring.
But write ten o’clock, nine a.m., ten p.m.
18. Festivals and historic or famous days.
Easter Day
Fast Day
Independence Day
Black Friday.
19. Stars, planets, constellations, and the like, except sun, moon, stars, earth.