Deviations may also result from different customs for the start of the day, i.e. dusk, sunset, midnight, dawn or sunrise. Furthermore, it may be accepted to have the respective starts of the astronomical season, the full moon and the Sunday may occur in a single calendar day as long as they are observed in that order. Fixed date It has been proposed that the first problem could be resolved by making Easter occur on a date fixed relative to the western Gregorian calendar every year, or alternatively on a Sunday within a fixed range of seven or eight dates. While tying Easter to one fixed date would serve to underline the belief that it commemorates an actual historical event, without an accompanying calendar reform that changes the pattern of the days of the week (itself a subject of religious controversy) or adopted a leap week, it would also break the tradition of Easter always being on a Sunday, established since the 2nd century and by now deeply embedded in the liturgical practice and theological understanding of almost all Christian denominations. The Second Vatican Council agreed in 1963 to accept a fixed Sunday in the Gregorian calendar as the date for Easter as long as other Christian churches agreed on it as well. They also agreed in principle to adopt a civil calendar reform as long as there were never any days outside the cycle of seven days per week. The Pepuzites, a 5th-century sect, celebrated Easter on the Sunday following April 6 (in the Julian calendar). This is equivalent to the Sunday closest to April 9. The April 6 date was apparently arrived at because it was equivalent to the 14th of the month of Artemisios in an earlier calendar used in the area, hence, the 14th of the first month of spring. The two most widespread proposals for fixing the date of Easter would set it on either the second Sunday in April (8 to 14, week 14 or 15), or the Sunday after the second Saturday in April (9 to 15). They only differ in years with dominical letter G or AG where 1 April is a Sunday. In both schemes, account has been taken of the fact that—in spite of the many difficulties in establishing the dates of the historical events involved—many scholars attribute a high degree of probability to Friday 7 April 30, as the date