The term century in the more common connotation that refers to a period of 100 years is relatively recent:
The Modern English meaning is attested from 1650s, short for century of years (1620s). (Etymonline)
From Middle English centuria
(a) A division of the Roman army: a century; (b) a Roman land measure. (Middle English Dictionary)
It appears that the Middle English term was used only to refer to a Roman army company consisting of approximately 100 men and to a land measure, and I can find no evidence it was used to refer to a cycle of 100 years.
What term or expression was used to refer to a period of 100 years or to a specific century, the 11th or the 12th for instance in Middle English and/or in Shakespeare's times?
Best Answer
A century is equivalent to hundred years and the origin of hundred dates back to Old English
From On the interaction between constructional & lexical change Copular, Passive and related Constructions in Old and Middle English
It appears in early Modern English, before the concept of century (i.e. 100 years) was adopted, phrases had to be employed. In A Christian directorie guiding men to their salvation, printed in 1585 the following phrases are used:
Today, we might express the first date as the 8th century / 714 A.D,
while the second, as being the 4th century / 333 A.D (or CE)
Lastly, the works of William Shakespeare contain eight citations for “hundred years”