a. Egyptians, at the time of moses and also before they choose Islam.
b. Palestinians at the time of David and also before they choose Islam.
c. Romans immediately before Constantine choose Christianity.
d. Goths and Gauls at the time of Roman Empires.
e. Mongols at the time of Ghengis Khan and Timur Lang.
f. Vikings.
g. Pakistanis before they choose Islam.
h. Latin countries before Spain and Portugal decided to visit them.
i. All Meccans and Medinians before Prophet Mohamed established Islam.
j. Chinese before they choose Budhism.
k. Aboriginals in Australia and New Zealand.
i. Iran before they choose Islam.
What happened to those earlier religions ? Whether everybody of them was converted or most of them ran away to safer lands or were they annihilated by new comers in different cases?

a-i: Pagans.
there is a difference before catholocism and christianity.
In most acses there was no ‘religion’ in the sense of organised public faith – with some exceptions. Ancient Egypt had a range of official cults (to Ra-Aten, Horus, Isis, etc.). The ancient Canaanites (Palestinians) also worshipped a range of Near Eastern gods (Baal, El, Asshur, etc.). The Persians (Iranians) were Zoroastrians prior to the arrival of Islam, the Vikings worshiped Germanic deities (Freyr, Thor, Oddin, etc.), and the Romans had a range of classical and more exotic cults which all coexisted relatively peacefully.The Mongols worshipped the sky god of the steppe, but converted to islam in the fourteenth century.
Most of the rest had no official ‘religion’ as such.
The ‘blanket’ answer is pantheists, polytheists, monotheists, pagans, animists, and why-does-this-sound-like-a-homework-question-theists.
ISLAM the is latest religion & the REAL religion
Its greate & usefull
Ask any one choose the ISLAM from USA, UK, GERMANY ….. why them choose the ISLAM ?!!
You can know the answer from that site But please read all of it to know the TRUTH
http://www.Islam-Guide.com
from the beginning of the world…..Allah sent many Messengers with the message of truth to the people………….
The Short Answer of your Question is:::::
In every circumvolution there were two types of people….
1) who accepted the message of truth
2) who rejected the message of truth.
All those who accepted the message of truth, were believers and their religion was Islam.
All those who rejected the message of truth, were disbelievers and they were antitheists/atheists/infidels
Hope this is the answer of your question.