The Roman Rite, originally celebrated only in the city of Rome and its environs, was adopted by other Western churches in an effort to introduce a fully organized and standardized liturgy.
Celtic liturgies show the wide-ranging influence of the Irish missionary-monks, who tended to appropriate liturgical elements from all parts of the Greek and Latin churches. The Celtic liturgy emphasizes a strong personal relationship with Christ and with the Trinity.
The Ambrosian, or Milanese, liturgy shared common features with both Western and Eastern rites and served as a link between them. A central feature of the Ambrosian liturgy is its Christocentric nature, reflecting an ongoing struggle with Arian influence. Never suppressed by ecclesiastical authorities, the Ambrosian liturgy continues in use today.
Ecclesiastical leadership in the Iberian peninsula held the liturgy in high esteem as a means of communicating the truths of the Christian faith. Spanish liturgical creativity, therefore, was marked by a stress on doctrinal precision.
Great diversity evidently existed in the liturgies used in southern Gaul. Lack of documentation, however, makes it difficult to reconstruct some parts of the liturgy. By the ninth century, the Gallican liturgy had become fused with the Roman rite. The spread of Roman influence is clearly shown by early Gallican sources.
It is thought that North Africa was the birthplace of Latin Christianity. Because of Muslim expansion, however, the church did not survive in North Africa beyond the eighth century. Since no actual texts of the ancient North African liturgy are extant, the outline of the rite can only be reconstructed from other sources.
While there is a common core to historic Western Christian liturgy, there is also considerable diversity. Rites differed from region to region and from place to place. Regional improvisations on the basic framework of the liturgy led eventually to a proliferation of liturgical books in the Western church, with many variations even within the same regional traditions.