Metal types of the Korean alphabet Hangeul and artifacts presumed to have been made during the reign of King Sejong the Great in the 15th century were excavated in central Seoul.

The Cultural Heritage Administration(CHA) said on Tuesday that some one-thousand-600 types, likely from the 15th and 16th centuries, were discovered at the site of an urban renovation project in Seoul's Jongno district.

Around one-thousand were Chinese characters, while about 600 were Hangeul, including what are believed to be the oldest forms of consonants found to date, which were used soon after the Korean alphabet was invented in 1443.

Key parts of an astronomical clock thought to have been made in 1437, as well as portions of a water clock, cannons and a copper bell from the 15th to 16th centuries were also found.

It is the first time that actual parts of the astronomical clock, referred to as "Ilseongjeongsiui" in Sejong Chronicles, were discovered.