When did Islam Begin and Who Started the Muslim Tradition?

Praise be to
Allaah.

If what you mean by
the “Muslim tradition” is the Islamic religion itself, the answer will
be given in the second section below. 

1-    
But if what you mean is
what the Muslim ummah (nation) has achieved down throughout the ages
of prosperity, then this was not achieved in one instant, but it started
when Islam started, especially after the establishment of the Islamic
state at the time of the Prophet

(peace and blessings of Allaah be upon him), then it started to flourish
and develop as the Islamic conquests spread and reached the level that
they did. If this can be attributed to anyone, it can only be attributed
to the Prophet

(peace and blessings of Allaah be upon him), after Allaah. With regard
to other people, everyone contributed as much as he could until the
structure (of the Muslim civilization) was complete.

2-    
With regard to the beginning of
the religion, it seems that what is meant by religion is the religion
of Islam with its beliefs and laws. This started with the mission of
the Prophet

(peace and blessings of Allaah be upon him). 

With regard to the
rules of Islam, they are many and it is difficult to list them all here,
but the most important of them are: 

The testimony that
there is no god except Allaah and that Muhammad is the Messenger of
Allaah; establishing regular prayer; paying the zakaah (obligatory charity,
a share of one’s wealth to be given to the poor); fasting in Ramadaan;
and Hajj or pilgrimage to the Sacred House of Allaah. 

An individual enters
this religion after bearing witness that there is no god except Allaah
and that Muhammad is the Messenger of Allaah, then after that he is
obliged to adhere to the other pillars, prayer, fasting and Hajj. There
are many further details involved in these matters. 

See
also Question # 13569