When were the Beautiful Names of Allah, known to Muslims, revealed? Were they known before Islam, or were they revealed to Muhammad (peace be upon him)? And how could the Prophet's father's name be "Abdullah" if Islam is what taught us the name "Allah"?

There is no text that specifies when the Beautiful Names of Allah were revealed. However, the majestic name "Allah" was known before the advent of the Prophet, peace and blessings be upon him. Its mention was frequent in the poetry of the pre-Islamic era (Jahiliyyah), such as the saying of Zuhair: "It became clear to me that Allah is truth, so it increased me in piety towards Allah, beyond what was evident," and the saying of Antarah: "May Allah not distance from my eyes valiant men humans when they dismount, jinn when they ride."