BM 108981 a two-column clay cylinder with an Akkadian inscription of the Neo-Babylonian king Nabonidus mentioning Ubassu. Photo credit: Frauke Weiershäuser.
An Akkadian inscription of Nabonidus (r. 555–539 BC), Babylon's last native king, states that he undertook work at Ubassu (modern Tell Aswië), a small town situated between Babylon and Borsippa. The exact nature of the project(s) there is uncertain as the passage recording construction activities in that town is rather vague:
That Neo-Babylonian king appears to have renovated or rebuilt a sanctuary of the goddess Nanāya. Nothing further about that unnamed religious structure is known, including its Sumerian ceremonial name.
Jamie Novotny
Jamie Novotny, 'Temples and Shrines of Ubassu', Babylonian Temples and Monumental Architecture online (BTMAo), The BTMAo Project, a sub-project of MOCCI, [http://oracc.org/btmao/Ubassu/]