Ismaili Muslims came from as far as Dallas and Chicago to hear their spiritual leader, Aga Khan IV, discuss the Aga Khan Awards for Architecture at a crowded Hirshhorn Museum auditorium last night.

His Highness' lecture on the qualifications that led to the selection of 15 building projects was only half the reason for the sojourn. The 43-year-old Khan is the leader of a well-dispersed religious faith. Ismaili Muslins, residing primarily in Asia, Africa and the Middle East and numbering between 12 and 20 million, look to His Highness as the direct descendant of Mohammed.

"This is an historical occasion," said Anwar Somani, an Ismaili engineer from Washington.

Nadir Mehareli, an Ismaili accountant from Dallas, agreed. "There's so much happening now. His Highness' concern with retaining the old structures rather than destroying them makes a lot of sense architecturally but also religiously."

The Aga Khan's lecture focused on the need to design ecological and cultural buildings using local resources and serving social needs.

The 15 winning projects of the first Aga Khan Awards for Architecture -- initiated in 1978 -- were presented in a slide show by Renata Holod, a professor in Islamic Architecture at the University of Pennsylvania. The awards will be given every three years to outstanding architectural achievements in the Muslim world.

The lecture and reception were co-sponsored by the Smithsonian Institution and The National Committee to Honor the Fourteenth Centennial of Islam. The awards, for projects built between 1950-1977, totaled $500,000 -- the largest architectural awards program in the world, according to the Smithsonian. The awards were officially presented last October in Pakistan by the Aga Khan.

"I have no particular favorites," said the Aga Khan when asked about hiw own choices for the awards. "I was not on the selection committee."

At his side was his wife, Her Highness Begum Salimah, as well as his half-sister, Princess Yasmin, daughter of his father Aly Khan and actress Rita Hayworth. Her Highness -- the former Lady Sarah Crichton-Stuart -- was wearing a paisley print dress with satin trim while the princess, who came in from New York for the event, was dressed in a festive blue and red print pleated dress.

The holiday season was evident in the attire of a number of the women including Eunice Shriver who wore a deep blue full-length sequined dress and coat and Mrs. S. Dillon Ripley in a gold and black brocaded dress.