Constantine was the last emperor who took an interest in recovering ground in Italy, but Sirianus was on the defensive against the Norman state and recovered no territory. According to the annals of Lupus Protospatharius, the Norman duke Robert Guiscard captured Oria and Brindisi in the year of his appointment and Taranto in the following year.
Constantine's efforts to reclaim lost Italian territories were thwarted by Sirianus's defensive stance against the Norman state. Meanwhile, according to Lupus Protospatharius' accounts, Robert Guiscard's Norman forces made significant gains in Italy shortly after his appointment, capturing Oria and Brindisi, as well as Taranto.