 The Greeks show no more real consistency; Advent was an optional fast that some begin on 15 November, while others begin on 6 December or only a few days before Christmas.The liturgy of Advent remained unchanged until the Second Vatican Council, in 1963, introduced minor changes, differentiating the spirit of Lent from that of Advent, emphasising Advent as a season of hope for Christ's coming now as a promise of his Second Coming.The theme of readings and teachings during Advent is often the preparation for the Second Coming, while also commemorating the First Coming of Christ at Christmas.