Catholicos Sahag II settles the Catholicosate in Antelias, in 1930. He makes one of his priorities the purchase of the property to be able to build the cathedral, and commissions his Vicar, Arch. Bedros Sarajian, to achieve this goal.

Mr. Levon Jamouzian of London, England, informs Archbishop Sarajian that an Armenian is interested in construction projects initiated by the Catholicosate but he wants to remain anonymous. Archbishop Sarajian consecrates the St. Gregory the Illuminator Cathedral on March 10, 1940.

On April 12, 1943, Arch. Mesrob Naroyan, Armenian Patriarch of Constantinople, informs that on March 24 the benefactor of the Antelias Cathedral, Mr. Sarkis Knajian, had passed away.

The St. Gregory the Illuminator Cathedral is an impressive building contsructed according to the Armenian architectural style under the guidance of architect Mardiros Altounian.