There is some­thing odd about how the ancient mosaicist of Raven­na’s church of San Vitale tells the sto­ry of Moses receiv­ing the Ten Com­mand­ments.  When God presents him with the law, Moses turns away.  His gaze is fixed on the mosa­ic below, in which God pre­vents Abra­ham from sac­ri­fic­ing his son Isaac, instruct­ing him to offer a ram instead, thus ful­fill­ing the patriarch’s expec­ta­tion that God him­self would pro­vide an aton­ing sacrifice.

San Vitale’s mosaics are sixth cen­tu­ry mas­ter­pieces of light and col­or.  They con­vey the Chris­t­ian gospel with inef­fa­ble elo­quence.  They also express polit­i­cal aspi­ra­tions, long-for­got­ten visions of what Europe might be.  Their dis­ap­point­ments rever­ber­ate today in the streets of Kiev, Odessa and Donetsk.

The mosa­ic of Moses and Abra­ham cap­tures the inter­play of law and grace, jus­tice and mer­cy, redemp­tion and faith that are at the heart of the Chris­t­ian gospel.  The artist tells us that while the law can con­demn, it can­not jus­ti­fy.  This real­iza­tion com­pels Moses to look away from the law and turn instead toward redemp­tive sac­ri­fice.  In the tra­di­tion­al Chris­t­ian under­stand­ing, the episode involv­ing Abra­ham and Isaac pre­fig­ures the cross, with God pro­vid­ing the sac­ri­fice that would deliv­er us from the law’s con­dem­na­tion.  That is why the mosaicist places a cross above his depic­tion of Abra­ham and Isaac.

Raven­na rose to promi­nence in the ear­ly 400s when the west­ern emper­or Hon­o­rius fled there to escape the Visig­oths, who had sacked Rome and abduct­ed his sis­ter.  His father Theo­do­sius, the last emper­or to rule over both East and West, had divid­ed gov­er­nance of the empire between his two incom­pe­tent sons, entrust­ing admin­is­tra­tion of the East to Galerius and the West to the hap­less Hon­o­rius.  In the arc of just a few years, Hon­o­rius had lost Spain and Gaul (France) to var­i­ous Ger­man­ic tribes and noti­fied the cities of Britain that Rome would no longer defend them against trib­al invaders.  Hon­o­rius died in 423.  By 476, his suc­ces­sor would relin­quish the impe­r­i­al stan­dards, send­ing them to his coun­ter­part in Con­stan­tino­ple.  In the­o­ry, the emper­or in the East now also ruled the West, though in prac­tice the west­ern half of the Roman Empire had disintegrated.

But the vision of a unit­ed Chris­ten­dom ruled by a sin­gle emper­or did not die with Hon­o­rius.  Its rebirth came more than a cen­tu­ry lat­er when Jus­tin­ian assumed the throne in Con­stan­tino­ple with hopes of restor­ing the Roman Empire to its for­mer dimen­sions.  His efforts met with ini­tial suc­cess in North Africa and Italy.  East and West were again united.

That achieve­ment is cel­e­brat­ed in the mosaics of Ravenna’s San Vitale, a church that Jus­tin­ian com­mis­sioned.   The emper­or appears in a mosa­ic in the apse, just a few feet away from the one of Moses receiv­ing the Ten Com­mand­ments.  It shows the emper­or and his ret­inue pre­sent­ing gifts at the altar.  The fac­ing wall por­trays the empress Theodo­ra and her entourage doing the same.  The mes­sage is unmis­tak­able: the emper­or rules in sub­mis­sion to God and in con­cert with his church.  His job was to defend the faith, the clergy’s to nour­ish it.

The emper­or proved unable to pro­tect the church in the West for very long.  The Lom­bard inva­sion of Italy reversed most of Justinian’s gains and his suc­ces­sors nev­er seri­ous­ly returned to the West­ern project, being pre­oc­cu­pied by the inva­sions of Arab Mus­lims that began in the 600s and that would even­tu­al­ly trans­form Chris­t­ian Con­stan­tino­ple into Mus­lim Istanbul.

The Lom­bard depre­da­tions in Italy prompt­ed Pope Stephen to cross the Alps in 753 to appeal to the Franks for mil­i­tary assis­tance.  If the emper­or in Con­stan­tino­ple couldn’t pro­vide him relief, per­haps a Frank­ish king could.  King Pip­pin came to the church’s aid.  By 800, Pope Leo had crowned Pip­pin’s suc­ces­sor Charle­magne “Emper­or of the Romans.”

What was acclaimed in the West – the union of much of West­ern Europe under the rule of Charle­magne – was con­demned in the East.  The Pope, it was argued, had no author­i­ty to name Charle­magne emper­or of the Romans.  There was but one emper­or, and he ruled from Con­stan­tino­ple.  The polit­i­cal rup­ture between East and West was complete.

That breach would widen over the cen­turies, as the­o­log­i­cal, cul­tur­al and lin­guis­tic dif­fer­ences proved irrec­on­cil­able.  The West pur­sued the ide­al of Charle­magne long after his empire had frag­ment­ed.  That ide­al came to very dif­fer­ent expres­sions in such fig­ures as Napoleon and Hitler and in diverse polit­i­cal insti­tu­tions like the Holy Roman Empire and the Euro­pean Union.

The East moved in a dif­fer­ent direc­tion.  A new seed was plant­ed in 987 when the ruler of Kievan Rus con­vert­ed to the east­ern ver­sion of Chris­tian­i­ty.  Kiev even­tu­al­ly was eclipsed by Moscow as the cen­ter of Russ­ian ortho­doxy, though the Ukrain­ian city still is regard­ed as Rus­si­a’s cra­dle.  When Con­stan­tino­ple fell to the Turks in 1453, Moscow came to be regard­ed as the Third Rome.  Its rulers called them­selves “czars” — Cae­sar, a title used by Roman emper­ors — and hewed to an east­ern under­stand­ing of the emper­or as pro­tec­tor of the church.

In many ways, Ger­man Chan­cel­lor Angela Merkel can be said to stand in the tra­di­tion of Charle­magne; Russ­ian Pres­i­dent Vladimir Putin in the tra­di­tion of the czars.  She is emphat­i­cal­ly sec­u­lar, hop­ing to build a unit­ed Europe gov­erned accord­ing post-mod­ern West­ern sen­si­bil­i­ties.  The EU now extends from the Unit­ed King­dom, through­out almost all West­ern Europe, and into ter­ri­to­ries for­mer­ly with­in Russia’s orbit.

Putin regards the spread of the EU and NATO into Rus­si­a’s tra­di­tion­al sphere of influ­ence as an encroach­ment.  He dreams of a Russ­ian-dom­i­nat­ed Eurasian Union that would stretch from Siberia to Poland’s east­ern edge and rival the US, EU and Chi­na as an eco­nom­ic and polit­i­cal pow­er.  Like Stal­in, who enlarged the Sovi­et Union’s bor­ders by recov­er­ing regions that had been ruled by the czars, Putin is said to seek to recon­sti­tute the Russ­ian empire to its pre-1917 dimensions.

Unlike Stal­in, Putin styles him­self as the defend­er of the Ortho­dox church.  The Patri­arch of Moscow has called Putin a “mir­a­cle from God.”  Putin has been known to seek spir­i­tu­al refresh­ment at an ortho­dox monastery.   Whether his piety is authen­tic, staged or a bit of both is imma­te­r­i­al.  It sym­bol­izes, in any case, his inten­tion to restore Rus­sia to impe­r­i­al great­ness and its his­toric East­ern under­stand­ing of the rela­tion­ship between church and state.

The roots of today’s cri­sis in Ukraine run deep.  It is no mere con­flict over ter­ri­to­r­i­al sov­er­eign­ty and self-deter­mi­na­tion or over the rel­a­tive mer­its of mil­i­tary inter­ven­tion and eco­nom­ic sanc­tions.  It rep­re­sents a clash of visions that pits a West­ern Europe devot­ed to sec­u­lar­ism, mate­r­i­al com­fort, income redis­tri­b­u­tion and demil­i­ta­riza­tion against a Russ­ian gov­ern­ment that cel­e­brates its reli­gious tra­di­tions and appears increas­ing­ly will­ing to employ force in pur­suit of its objectives.

One gets the sense that Pres­i­dent Oba­ma is intrud­ing into an argu­ment between peo­ple whose lan­guage he doesn’t speak.  While oth­er world lead­ers pur­sue dreams – of a unit­ed and sec­u­lar Europe, a resur­gent Russ­ian empire, Chi­nese hege­mo­ny, or the impo­si­tion of sharia law – Pres­i­dent Oba­ma labors under the illu­sion of his own inerran­cy.  As he said recent­ly in Mani­la, his for­eign pol­i­cy “avoids errors.”

There is good rea­son to dis­pute that.  But how­ev­er one assess­es the Pres­i­den­t’s record, his for­eign pol­i­cy is increas­ing­ly regard­ed by allies and foes alike as dimin­ish­ing Amer­i­can influ­ence on world affairs.  The Pres­i­dent seems to aspire to a US that humbly takes its place in the com­mu­ni­ty of nations, even as promi­nent mem­bers of that com­mu­ni­ty seek to engen­der, has­ten and shape a post-Amer­i­can era.

The mosaics of Raven­na were craft­ed in an age when Europe was dra­mat­i­cal­ly and irre­versibly remade.  The upheaval cap­tured in its mag­nif­i­cent art and archi­tec­ture still is felt in our own age.  It is far too soon to know whether the crises of our era will bear sim­i­lar his­tor­i­cal significance.

But it would help to know that the Amer­i­can leader has at least some sense of where he is tak­ing us and what may be at stake.