The argument is also made that since the use of the Julian calendar was implicit in the decision of the First Ecumenical Council at Nicaea (325), which standardized the calculation of the date of Easter, no authority less than an Ecumenical Council may change it. It is further argued that the adoption of the new calendar in some countries and not in others has broken the liturgical unity of the Eastern Orthodox churches, undoing the decision made by the council of bishops at Nicaea to decree that all local churches celebrate Easter on the same day. The emperor Constantine, writing to the bishops absent from the Council to notify them of the decision, argued, "Think, then, how unseemly it is, that on the same day some should be fasting whilst others are seated at a banquet".