A mainstream Muslim website recently declared that the Imam Mahdi will appear either this year or in 2016, and that Jesus will return in 2022.
DiscoveringIslam.org and the End Times Research Center believe the first phase of the End of Time will begin soon, and lead to the Day of Judgement in seven years.
The estimates were derived from "Numerical Analysis of the Quran, Hadith, Arabic Words, and Historical Events," according to the organisation's website.
"The Messenger of Allah [sallallahu 'alayhi wa-sallam] informed the Companions of everything that would occur until the Day of Resurrection," they wrote.
According to Discovering Islam, some of the signs indicative of the Last Days have already occurred, including "the conquest of Bayt al-Maqdis, the plague of 'Amwas, the widespread abundance of wealth, the conquest of the Arabian Peninsula, Sham, Persia, Egypt, India and Sind," and other events.
They purport that other signs "have appeared and are continuing and increasing," such as "usury becoming widespread, lying, deceit and false witness becoming common, the coming to authority of those unworthy of it, the death of the scholars, the disappearance of knowledge".
Finally, there are the signs that have not occurred: "the Euphrates uncovering a mountain of gold, the Arabian Peninsula becoming meadows and rivers, the transformation of people in this Ummah into apes and pigs due to their considering major sins as lawful," and more.
The Mahdi is not explicitly referenced in the Koran, but appears in the Prophet Muhammad's compilation of teachings, known as Hadith. Some Muslims believe he will return to rule for seven years, and will eradicate all evil.
The Research Center's book, "The End Times: Based on Numerical Analysis of the Quran, Hadith, Arabic Words, and Historical Events," provides more information on how their predictions were derived, and the false witnesses they believe will trigger the End of Time period and the End of Days.