ROME.- Room X of the Baths of Diocletian, one of the largest rooms in the monumental complex, has reopened after thirty years of renovations.

The Baths of Diocletian in Rome were the grandest of the public baths, or thermae built by successive emperors. Diocletian's Baths, dedicated in 306, were the largest and most sumptuous of the imperial baths and remained in use until the aqueducts that fed them were cut by the Goths in 537. Similar in size and plan to those of Caracalla and oriented to the southwest so that solar energy heated the caldarium without affecting the frigidarium, they are well preserved because various parts later were converted to ecclesiastical or other use.

Built between 298 and 306 AD, these were the greatest of the Imperial baths. The perimeter wall, enclosing a quadrangle of 14 hectares, was colonnaded along the inside and contained chambers and rooms for different uses. On the long axis of the building, Via Gaeta, marking the northern side, is where the public was admitted into the changing rooms, the gyms, and the massage rooms.

On the short axis, following the old floor plan of Trajan's Baths, stood the Basilica, the hot baths of the calidarium, the tepid baths of the tepidarium, and the swimming area. The great exedra of the baths, today's Piazza della Repubblica, was also part of the perimeter walls and was used for theatrical shows.

Over the centuries, many of the chambers of the baths were restored and used for museums, university faculties and churches.

Although the building has undergone a great number of changes, the floor plan of this enormous bath complex, purportedly built by 40,000 Christians, is still easily recognizable today.