I've been trying to compile a timeline of development of various aspects of church architecture, furnishings and chant. There are many things that we will assume to be "Western" developments, and yet, many can be found before even the schism. I wanted to write about some of these developments and how they actually can be considered to be just as part of our Orthodox tradition as our own Byzantine traditions.
Iconography, well all know it comes directly from the first century and was continued in the Christian tradition as it was from the Judaic tradition. Many of the earliest images include not just Old Testament figures, but pictures of Saints, of Christ as the Good Shepherd, of Fish, of wine/grapes, of plants, of animals, etc...
Engraving and reliefs also comes from the first century in Christian history. Here you find Christians carving images into stone. This becomes much more refined and developed as time goes on, and when Christianity is legalized, we see this entering the Churches with furniture carved out of marble and stone, or elements of architecture such as columns, friezes, etc...
The Ambo dates to about the 3rd century. This was typically a stone or wood platform which had several steps leading up to it. It was the ancient predecessor to the pulpit. Originally they sat in the center of the Church directly in front of the "templon" (later iconostasis), and were eventually moved to the side of the Church. In the Russian tradition today, the steps leading up to the sanctuary/chancel have a section protruding out in front of the Royal Doors, and so in the Russian tradition, this acts as the Ambo. The Greek churches still retain and use the elevated platform.
In the 4th Century, we see the development of the Basilica Church and the Central Church. These two were prototypes taken from Roman precidents. Central Churches typically acted as matryriums, baptismals and other secondary spaces. The Basilica became the primary layout for the Church, and was best suited to the services of the Church.
Stained/Colored Glass in Church Architecture is also first found in the 4th Century. Most Churches had alabaster-colored glass, but there are remnants of glass of other colors found from 4th/5th Century Churches. One such example can be found at the Byzantine Museum in Thessaloniki, where there is colored glass from a Church (I think from the 5th/6th Century) that is colored green, blue, clear, etc... So it is important to keep in mind, that stained/colored glass is not something new to Orthodox Churches, and has existed for nearly 2000 years in ecclesiastical architecture.
Two church architectural styles also originate in the 4th century. These two being the Byzantine Style and the Coptic Style.
Church Statuary also seems to originate in the 4th Century. The initial statues that could be found in Churches seem to be statues of Christ as the Good Shepherd. This would make sense, as the Greeks already had statues of the "Calf-Bearer" and so the Christian image of Christ as the Good-Shepherd (holding a lamb) would be a natural replacement, and probably easier for sculptors to craft. So today, when we see statuary in Orthodox (or even Catholic) Churches, we must remember that this is a tradition dating back to the 4th Century, and isn't something extremely new.
The Templon first appears in the 5th Century. The Templon was placed between the Sanctuary and the Nave as a method of division. It was composed of several tall columns that had slabs placed between them at the ground level (usually carved with crosses, plants, animals, etc...) and at the top, they had a cornice/beam running across. This was the ancient predecessor of the iconostasis, or rood screen. At this point, it had not been filled with icons, and one could see through to the altar. Most iconostasis today are still constructed much like the templon, but have icons filling the openings between the columns...
Gallican Chant as we know it today also seems to develop in the 5th Century.
In the 6th Century, we see the appearance of Church Bells. At first, I think they were smaller in nature, but later became larger.
The Pre-Romanesque Architecture Style also first appears in the 6th Century.
Celtic Chant appears in about the 6th Century.
The Benedictine Order of monasticism in the West first develops in the 6th Century.
In the 7th Century, Church Organs first appear to be used, though their precise usage may be unknown. It is interesting to note though, that the use of organs in liturgical worship is also not something new.
Mozarabic Chant and the Mozarabic Rite also appears in the 7th Century.
We first see the Cross-In-Square style develop in the 8th Century. This is the style that dominates the Orthodox tradition, and is the combination of the basilica church and the central church.
Byzantine Chant, Ambrosian Chant, Old Roman Chant & Beneventan Chant as we know them today also seem to have developed in the 8th Century. Byzantine Chant is largely based on Eastern Chanting Styles prior to the 8th Century (eventually going back to Judaism). Most Western Chants also owe their ancestry to Eastern Chant, but eventually developed into their own styles.
The Gallican Rite as we know it today also developed in the 8th Century
This is the first period we begin to see the Semantron develop. This is slab of wood that is struck with a hammer in order to call people to prayer. It would become extremely common during Muslim domination, as Muslims would ban the use of bells.
The Celtic and Durham Rites also develop during this period.
By the 10th Century, we finally see the iconostasis fully develop from the templon. We also see the rood screen develop by this period.
Gregorian Chant first develops during this period. It is interesting to notice this, as we most often associate Gregorian Chant with the Post-Schism Roman Church, but it pre-dates the Schism, and owes it's ancestry to Western Chants (which owe their ancestry to Eastern Chants).
This is also the century where we first see development of the "Pre-Tridentine" Roman Mass.
This is the period during which the Patriarch of Constantinople and Cardinal Humbert of Rome exchanged excommunications. While the Schism is dated to this period, it is interesting to note there was continuous inter-communion and con-celebrations occurring, even amongst monastics up until the 13th Century.
In Orthodox Churches, we first see the development of "double ambos", where there would be two ambos instead of one in a church.
The Sarum Rite appears during this period.
Romanesque Architecture first starts developing during this period.
The Cistercian Rite develops.
This period marks the final straw during the Great Schism, and very soon afterward, inter-communion and con-celebrations cease virtually completely, and the last Benedictine Monastery on Mount Athos closes.
The Franciscan and Dominican Orders develop during this century.
Altar and communion rails appear in Western Churches. The ancient Templon has developed into the Rood Screen, and is then lowered to become an altar/communion rail. Eventually it will dissapear alltogether in the Western Churches.
This period marks the fall of Constantinople and the rest of the Byzantine Empire to the Ottoman Turks.
The Renaissance Architectural Style develops during this century.
With the Protestant Reformation, we see the addition of Pews to Church Architecture in the West. Prior to this period, everyone stood for worship in the East and the West.
The Tridentine Mass is finally introduced in the Roman Church, and all existing rites are conformed to the Roman Rite.
Byzantine Notation is developed.