Athens - Forty-five shipwrecks, many dating back to ancient times, have been discovered off a Greek archipelago that is one of the Mediterranean's richest underwater archaeological sites, authorities said on Monday. In addition to the wrecks found off the Fourni islands in the Aegean Sea over the last two years, researchers also spotted anchors and hundreds of ceramic objects, Greece's ministry of culture said in a statement.Some 23 sunken vessels were found in 2016, with another 22 uncovered last year, including wrecks from the Roman era as well as the Archaic period which is some 800-480 B.C. The Fourni archipelago, home to about 1 000 residents, "is one of the richest [shipwreck sites] in the Mediterranean," the statement said. The ceramic objects and anchors are "evidence of navigation and trade off the archipelago that includes natural ports and kilometres of coast," the statement said. It "was a commercial maritime crossroads."Interesting wrecks found in 2016 include one from the Roman epoch which carried amphora and comes from the Black Sea, while another dates to the third to fourth centuries and is from Roman colonies in North Africa. Other discoveries are possible, as the underwater archaeological work off Fourni has only covered 15% of the coast and is set to wrap up in 2018.