Archaeologists excavating a site in northeastern Portugal discovered 4,500 ancient Roman coins tucked away inside a wall.

The bundle of 4,526 copper and bronze coins was hidden inside the wall of a 4th-century blacksmith's home, said Antonio Sa Coixao, who is leading the excavation in Coriscada.

The sack holding the coins appeared to have disintegrated, he said.

"It looks like someone was trying to hide them but they never went back to get them," Sa Coixao said Wednesday.

Archaeologists excavating the site — believed to be an ancient Roman village — came across the coins Friday. Sa Coixao said he planned to send the coins to the University of Lyon, in France, to be cleaned and catalogued.

In addition to the blacksmith's home, the excavation site, about 180 miles from Lisbon, includes a spa and a large house with heated rooms and colorful mosaics. The dig is expected to last several years.