Roger Bacon, an English Friar, dispatched his faithful servant John, with a manuscript ‘Opus Maius’ addressed to Pope Clement IV with an urgent appeal to correct the calendar by 9 days.
Unfortunately Pope Clement IV died, probably before he had a chance to read ‘Opus Maius’.
It took 300+ years before the correction identified by Roger Bacon was implemented, when Pope Gregory XIII corrected the calendar in 1582 CE.
Krishna, along with Pandava brothers and few others, met Bhishma – who was lying on bed of arrows, already, for more than 40 days.
Since Bhishma was waiting for the first day of Uttarayan (day of Winter solstice), Krishna told Bhishma, at this time, that Bhishma had 56 more days to live.
Mahabharata narration precisely walks us through Yudhishthir -Bhishma Samvad (discussion) of 6 days, followed by Yudhishthir living in Hastinapur for 50 days, leading to the day of Bhishma Nirvana (i.e. the day of Winter Solstice when Bhishma passed away).
Bhishma passed away on 31 January 5560 BCE, exactly 56 days after Krishna had mentioned the ‘waiting period for Bhishma’.
Bhishma was on bed of arrows for total of 98 nights (25 October 5561 BCE – 31 January 5560 BCE).
While it is hard to say how far before Roger Bacon, western Europe achieved an accuracy,comparable to that of Roger Bacon in 1267 CE or that of Krishna in 5561 BCE, we certainly know that it was not achieved until after the time of Ptolemy.