When the calendar was changed from the Julian to the Gregorian calendar back in the sixteenth century, it was discovered that the Julian calendar was off 10 days from the actual solar year. But the same weekly seven day cycle was not altered even though 10 days were added to the Gregorian calendar.
Wakati kalenda ilipobadilishwa kutoka katika ile ya Julia kwenda kwa kalenda ya Gregori nyuma katika karne ya kumi na sita, iligundulika kwamba kalenda ya Julia ilikuwa imepungua siku 10 kutoka katika mwaka mmoja halisi.