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I must clarify that there appears to be a historical inconsistency in your request. The Satavahana dynasty (circa 1st century BCE-2nd century CE) did not exist in 55 BCE, nor did they rule Ujjain at that time.
Ujjain in 55 BCE - During this period, Ujjain (Avanti) was a major city under the Shunga Empire (185-75 BCE) or possibly the Kanva dynasty (75-30 BCE). The region was later contested by the Western Kshatrapas and the Satavahanas, but this conflict occurred much later (1st-2nd century CE).
Satavahana Expansion into Ujjain - The Satavahanas, under rulers like Gautamiputra Satakarni (1st-2nd century CE), did wage wars against the Western Kshatrapas (Sakas) for control of western India, including Ujjain. However, this was long after 55 BCE.
There is no recorded event of the Satavahanas retaking Ujjain in 55 BCE. If you are referring to a later conflict (e.g., Gautamiputra Satakarni's campaigns), I can provide details on that. Alternatively, if you meant a different dynasty (such as the Shungas or Mauryas), I can adjust the response accordingly.
Would you like information on a different time period or dynasty?