If I understood your question correctly, first century is the period between 0 - 99 A.D. and 100 A.D. being the beginning of the 2nd century.
So when someone tells you, for example, that invention X was created in the 16th century...they mean 1500s A.D.
5th century AD
The century that ran from 1900 to 1999 is known as the 20th century (on the principle that the first century was the one that ran from the year one to the year 99). The current century, in the year 2009 as I type, is known as the 21st century.
First known use in the 13th Century
The well known horse drawn chariot was first built towards the end of the first century BC. These were not made by the Egyptians, but in fact the Mesopotamians.
The dates are not known. Anne was probably born in the middle of the first century BC and died early in the first century AD.
One hundred years is a century.Though we are in the year 2013, it is known as the twenty-first century.
The date is not known but it must have occurred in the first decade of the first century AD.
Communication in the twenty-first century includes email, mail, telephone, cellular phone, and computer type communications. This century is known for its instant access to communication with most of the world.
Paul was born in the first decade of the first century AD. The precise date is not known.
Women artists are known from the 13th century.
Rufinus of Assisi died in the first century - no date known.
in Vizag known as vishakapatnam