1901 might also be an artefact of data with invalid dates passing through legacy systems that only support dates between 1901 and 2099 (because both 1900 and 21

1901 might also be an artefact of data with invalid dates passing through legacy systems that only support dates between 1901 and 2099 (because both 1900 and 2100 are non-leap years divisible by 4, breaking naive time calculations).