President Obama’s best friend in Turkey is surrounding himself with guards dressed like the 15th century Turkish soldiers who captured Byzantium, the Roman Empire’s last capital city.

The garish display of imperial grandiosity was staged Jan. 12 by President Tayyip Erdogan, the recently re-elected president of Turkey, as he welcomed Arab strongman Mahmoud Abbas to Turkey’s new imperial palace.

Erdogan descended a staircase toward cameras, while flanked by guards dressed in military costumes of the Turkish military, dating back to 1299.

Erdogan’s display spotlighted the unbridgeable gap between his ethnic ambitions and Obama’s early hopes of working with Turkey to suppress the various Islamic and ethnic wars in the Middle East.

Back in January 2012, Obama described Erdogan as one of his best five friends among foreign leaders. “The bonds of trust that I’ve been able to forge with a whole range of leaders is precisely, or is a big part of, what has allowed us to execute effective diplomacy,” Obama told Time magazine.

In March 2012, Obama declared that “the bottom line is that we find ourselves in frequent agreement upon a wide range of issues … [and] because he has two daughters that are a little older than mine — they’ve turned out very well, so I’m always interested in his perspective on raising girls.”

To build the desired alliance, Obama repeatedly talked to Erdogan by phone, met with him several times, and sent Vice President Joe Biden to Turkey. Most of those meetings were failures.

“We’re looking for Turkish leadership in the rest of that entire region,” Biden told Turkish business executives during a 2012 fundraiser.

Obama’s ambitions were gradually abandoned as Erdogan became increasingly dictatorial, Islamic, corrupt and anti-Semitic, and as he aided jihadi attacks on Israel, brokered embargo-busting trade deals with Iran and tried to make Turkey the dominant regional power.

That collapse was accompanied by the failure of Obama’s pro-Islam policies to keep peace in Syria, Egypt, Libya, Mali, Yemen, Iraq, Kurdistan and along Israel’s borders.

Erdogan has repeatedly called for Arabs to accept greater leadership from Turkey, a move that would partly revive the Turkish-led Ottoman Empire that ruled the Arab world for 600 years.

Few Arabs want to accept Turkish leadership, partly because Turks are their own ethnic group, distinct from Arabs.

The Turkish tribe emerged from Central Asia in 1299, and quickly overran the Arab world. The Turks’ empire is called the Ottoman Empire because the Turkish word for chieftain was “Osman.”

The Ottoman army captured Byzantium in 1453, using cannons built by rented Bulgarian mercenaries to wreck its massive walls.

The victory ended the 650-year war between expansionist Arab Muslims and the Christian emperors of Byzantium, and it drove Byzantium’s royal family into exile.

One surviving descendant, David Paleologos, is the director of Suffolk University’s Political Research Center.

Byzantium was renamed Constantinople. In 1930, it was renamed Istanbul. The name change was marked in a popular song.

In 1571, the Ottomans’ westward expansion was blocked when its fleet was destroyed by a multinational European fleet in the battle of Lepanto.

The Ottoman empire reached its zenith in 1683, when it sent an army to capture Vienna in Austria. That’s the same year that 13 Mennonite families from Germany founded the city that would become Philadelphia. The siege was broken by a European army, led by a Polish cavalry force.

The United States Navy was formed in 1798 to defeat slave-raiders and pirates sent out into the Mediterranean by provincial rulers in the Ottoman Empire. The memory of the “Barbary wars” echoes in U.S. popular history because of the “shores of Tripoli” line in the U.S. Marine Corps’ anthem. The memory also survives on Europe’s southern coasts, which are studded with many small castles which were built to foil the Ottoman’s effort to capture Europeans for the empire’s slave markets.

The empire was wrecked in 1798, when Napoleon captured Egypt. The Ottoman Empire was formally dissolved in 1920, when the British and French victors of World War I split the Ottoman empire into today’s Arab countries.

At the same time, Turkey was taken over by a young army officer, Kemal Ataturk, who modernized Turkey by abolishing the Ottoman Empire’s government. Ataturk secularized the government, and shoved the Ottoman Empire — complete with its alphabet, fashions and dreams of empire — into history’s trash bin. He also turned the main mosque in Constantinople into a museum.

The mosque was a Christian cathedral until it was captured by the Turks in 1453.

Erdogan is trying to revive Ottoman culture, partly by teaching Islam and the Turkish alphabet in schools, but also by dressing his guards as Ottoman warriors and by building a massive palace in Ankara, Turkey’s capital city, which is located in central Turkey.

Erdogan is definitely popular outside the country’ secular cities. Much of his support comes from traditional Muslims in the country’s large rural population, but he’s facing strong opposition from many younger Turks.

Starting in 2013, younger Turks in Ankara protested Erdogan’s corruption and authoritarianism. The protests were dramatically suppressed by Erdogan’s government.

He’s also facing growing problems with the country’s poor Kurdish ethnic minority.  Their population is growing so fast they’ll be in a position to fragment the country in a few decades.

Already, their clout forced Erdogan to reluctantly allow the transfer of military aid to reach a Kurdish town in Syria, just beside Turkey’s border.

Follow Neil on Twitter