Officials in the historic district of İznik in the western Turkish province of Bursa are working to submit an application for inclusion of the district on UNESCO's World Heritage List, an addition that would come on the heels of the inclusion of the ancient Ani ruins in the city that was the capital of the Bagratid Armenian kingdom in what is now far eastern Turkey. The district of İznik, which was added to UNESCO's tentative list in the past, has a history going back 2,400 years.Known as Nicaea in Greek, the region is described in the Christian world as the third holy city after Jerusalem and the Vatican and is an important holy site. In addition to the historic Haghia Sophia Church, another church was unearthed during excavations conducted under Lake İznik two years ago. İznik Mayor Recep Altepe emphasized the district's importance for Christianity in a meeting with the press last week.İznik is also known for its traditional ceramic tiles which appeared in architecture around 3,000 B.C., which Seljuks also arrived thousands of years later. Ceramic art peaked in the 13th century and adorns many historic palaces and mausoleums. İznik tiles were first produced in their current form in the 15th century during the Ottoman era. The most favored colors were purple, blue and crimson. Ceramic art enjoyed a golden age in the 16th century when the Ottoman Empire was most powerful.