October 20th, 1264 was a Monday.
September 24th, 1264 - October 23rd, 1264
Why not celebrate an alternative birthday? In 772 days, exactly on September 5th, 2028, people who were born on October 20th, 1264 will be 279,000 days old!
Fixed holidays (Christian feast days) which are celebrated on October 20th.
| M = 1000 | C = 100 | L = 50 | X = 10 | IV = 4 |
Yes: 1264 is a leap year, therefore has a 29th of February with an additional leap day and a total of 366 days (instead of the usual 365 days in a normal year).