The church year begins with the first Sunday in Advent, but Bach started his first Leipzig cycles on the first Sunday after Trinity, which "also marked the beginning of the second half of the Lutheran liturgical year: the Trinity season or "Era of the Church" in which core issues of faith and doctrine are explored, in contrast to the first half, known as the "Temporale" which, beginning in Advent and ending on Trinity Sunday, focuses on the life of Christ, His incarnation, death and resurrection".