What do you mean by term Unity

a whole, a totality where all the parts collaborate and actively included. In other words, no part is split off, separated, dissociated.

Explanation: unity is opposed to dis-unity, integrity means that all parts are integrated into one whole.

in 342 bc j._c. egypt fell into the hands of the persians, under the reign of nectanebo ii

greek city-states unite in a revolt against the persian empire at the beginning of the fifth century bc. j.-c  

from the year 660 or 659 bc ad, cyrus preached the revolt against the medes to deliver the persians.

they encountered severe weather for which they were poorly prepared.