The huge crowds gathered for a mass ceremony on the outskirts of Istanbul for what Turkish authorities described as “the biggest ever celebration in modern Turkey’s history.”

To mark the occasion, the Turkish armed forces formed a 562-strong ceremonial brigade dressed as Ottoman soldiers. An Ottoman military band played conquest songs.

A passage from the Quran was recited on the stage as crowds waving flags shouted slogans in favour of President Recep Tayyip Erdogan and the Islamic-rooted ruling Justice and Development (AKP).

Erdogan, who is supposed to be apolitical as head of state but has in recent days been vigorously campaigning ahead of parliamentary elections on June 7, hosted the event along with Prime Minister Ahmet Davutoglu.

He was earlier premier for more than a decade and now wants the party to win a two-thirds parliamentary majority to change the constitution and create a presidential system.

“To make Turkey stand up on its feet again is a conquest,” said Erdogan, suggesting that the AKP’s 12-year stint in power was as triumphant as the Ottoman sultan Fatih Sultan Mehmet’s conquest of Istanbul.

“To reverse this nation’s ill fate for 12 years is a conquest. To successfully pass this turning point on the way to a new Turkey is a conquest,” he told the crowds.

“June 7 (elections), God willing, will be a conquest,” he added.

Sultan Mehmed II conquered Constantinople on May 29, 1453 at the age of 21, bringing an end to the Byzantine Empire.

Latest opinion polls suggest the AKP’s support could fall sharply from the almost 50 percent of the vote it garnered in 2011 with it possibly even losing its parliamentary majority.