In a corner of the second floor of the Smithsonian Museum of Natural History in Washington DC are some of the artifacts from Nelson Glueck's expedition to the Red Sea Port of Akaba (Aquaba), Jordan (published 1941). Perhaps the most spectacular find was the signet ring of Jotham . The copper or bronze ring was inscribed in Hebrew as "belonging to Jotham (YTM)."  The Jotham signet ring may have been owned by a seal bearer of the king. The ancient Egyptians granted certain royal officials the authority to use a royal seal stamp and it is probable Israel also used seal stamps as the clay vessels for wine, oil, and grain vessels were stamped with a seal before being fired in a kiln to designate that they belonged to person whose seal impressions was apparent. Seals were also affixed to scrolls bound with string. Seals were placed between the jamb and door of closed storerooms to show no one had opened them.

The signet ring was important evidence to support at least part of a  statement in  2Chronicles 26:1 that Uzziah was 16 when he started to reign.  He rebuilt Elath and reigned for 52 years ...." Jotham his son reigned in his stead."  This part of the Judean dynasty occurred through the first half of the 8th century.