Matthew was the Roman commandant at Pelusium in Egypt. Tribonian thought he was bitter-looking, and no doubt had been sent to Pelusium as a punishment. Matthew listened to Tribonian's reason for being there, to prevent the arrival of the plague, with disbelief, but agreed to help Tribonian as Justinian commanded. When Tribonian explained he needed access to the Red Sea, Matthew happily sent him on to Clysma.
↑Lest Darkness Fall & Timeless Tales Written in Tribute (second edition), pgs. 397-398, loc. 5210-5228, ebook.