Oh Tetrarch, my Tetrarch

Why were the tetrarchs named the tetrarchs?<br /><br />Question is asked from the sense of someone who lived in the setting and worked on Laco, digging at the Tetrarch ruins chose the name Tetrarch. So why was that?<br /><br />1. Sometimes things get named erronously- Queen's chamber in the Great Pyramid is one such- no queen was interred there but the name stuck.<br /><br />2. Could be that an expert intuitively chose an apt name based off what he was seeing in the ruins on Laco.<br /><br />Either way, there is something on Laco that prompted the name Tetrarch.<br /><br />Name means litterally rule of 4 and was used as a political title when Alexander the Great's kingdom was split up between his 4 generals, also used by 4 roman emperors under the Tetrarchy, and was used as a military title.