According to this website, the birth of Guru Nanak, the founder of Sikhism religion, is said to have been foretold in the scriptures. Though most of the verses they quoted were feeble attempts to potray Nanak as an incarnation, I found one interesting verse from the Vishnu Purana they quoted:
In the Vishnu Purana there is recorded an interesting dialogue between Vishnu and a famous Rishi Umbreek. Vishnu is said to have informed Umbreek that he will once again take birth in the Kali Yuga. The Rishi then enquired when about will that be and what will be your name then? Vishnu replied that this will happen when the Kali Yuga has proceeded for 4500 years and that I will take birth in the Shatri Sooraj Bansi clan, when I will be named, Nanak.
In this same Purana it is further recorded:
"Sri Nanak santang saageaami Sri asech, sri asech, sri asech, sri asech"
English meaning: "Sri Nanak will once again appear in the world in a variety of incarnations; this is for sure, this is for sure, this is for sure."
Computing the date of Guru Nanak's birth from the above mentioned figure that took place when the Kali Yuga had proceeded for 4550 years, reckoning the total durations of Kali Yuga now to be about 5090 old. It is to be noted that this figure of 4550 is pretty close to the 4500 years predicted by Vishnuji above. Incidentally, the clan in which Guru Nanak was born was also known as a Shatri Sooraj Bansi indicated above.
Is the site correct to say such verses exist in the Vishnu Purana?