When was Islam founded?
People have a misconception that "ISLAM" Is a "NEW RELIGION" which came into existence 1400 years ago... and that prophet Muhmmad peace be upon him is the founder of that religion .
Islam means: "Acquiring peace by submitting your will to almighty God"
And anyone who submits his will to god he is called as a Muslim And we know that Adam peace be upon him is the first person who placed his foot on planet earth and we know that Adam (pbuh) is a person who submitted his will to almighty God
Islam existed in the begining of time since man placed his foot on earth.
And Prophet Muhammad Peace be upon him is not the founder of that religion but he is the last and final messenger and ALLAH (SWT) clearly mentions in Surah: Ahzab chapter 33 verse 40 :
Muhammad is not the father of [any] one of your men, but [he is] the Messenger of Allah and last of the prophets. And ever is Allah, of all things, Knowing.
[QS. Al-Ahzaab: Verse 40]