Bisantius Guirdeliku (or Bysantius Guinderlichus) was a noble citizen of Bari, then the capital of the Byzantine catepanate of Italy.
It managed to break the Norman blockade and enter the harbour of Bari only after suffering severe losses.
Emboldened by the Byzantine military presence, he began a war of words with Argirizzo which sometimes devolved into skirmishing in the streets between their factions.
[1] The Ystoire de li Normant of Amatus of Montecassino provides the most details about the feud between Bisantius and Argirizzo during the siege.
[4] The exact day of Bisantius' death is supplied by the Anonymi Barensis Chronicon, which attributes his murder to "evil men" and does not name Argirizzo.