What can change the calendar in iPhone/iOS to start weeks on Mondays and not Sundays? My iPhone's calendar, configured by me to start week Sundays, suddenly started starting week Mondays. I cannot find the setting to configure this any more. I found when I switch the phone's region settings from Irish (I am in Ireland) to US, the weeks start Sunday again, but then PM times are shown as 4:06 (rather than 16:06).

What can I do to have my weeks shown properly and the time in 24 hours and remain in my local region?
24-hour vs 12-hour time is set in Settings=>General=>Date &amp; Time:



The Sunday vs. Monday thing may be entirely dependent upon the International setting; there's no explicit place to change it, anyway.