1. Measuring Time Periods of History
Eras: larger blocks of time ex. Prehistory (time before developed writing)
Decade: a period of 10 years
Centuries: a period of 100 years
Millennium: a period of 1,000 years

2. Measuring Time Dating Events B.C. “Before Christ”
B.C. E. Before the Common Era (modern reference)
A.D. Anno Domini “in the year of the Lord”
C.E. the Common Era

3. Prehistory Ancient History Middle Ages Modern history
Using Time Lines
Prehistory Ancient History Middle Ages Modern history
Up to 3500 B.C.
3500 B.C. to A.D A.D 500 to A.D After A.D. 1400
B.C B.C B.C B.C A.D A.D A.D AD. 1500