When will Maitreya Buddha come according to the Manimekalai?

According to Buddhism, Maitreya Buddha is a Buddha who will come some time in the future. Some sources say he will come hundreds of thousands of years from now, but the [Manimekalai](https://en.wikipedia.org/wiki/Manimekalai) , a 6th century Buddhist epic poem written in the language Tamil, seems to suggest an earlier timeframe. [Here](https://ia801406.us.archive.org/BookReader/BookReaderImages.php?zip=/20/items/manimekhalaiinit031176mbp/manimekhalaiinit031176mbp_tif.zip&file=manimekhalaiinit031176mbp_tif/manimekhalaiinit031176mbp_0184.tif&scale=8&rotate=0) is what chapter 12 of the Manimekalai says: > That dharma, people in this world do not know. But within the circuit of this universe, the devas understand it and at their request **the Deva will come down again to this world from the Tushita Heaven in the year 1616**. Then everyone in this world will feel impelled to practice the doctrine or mercy. My question is, what is this year "1616" that the Manimekalai identifies as the year when Maitreya Buddha will come? What calendar is it using? It's clearly not the Gregorian calendar, since that wasn't in vogue in 6th century India.