Short answers, pulled from the story.
Eustathius of Thessalonica was a Byzantine Greek scholar and Archbishop of Thessalonica who lived from around 1115 until approximately 1195 or 1196. He is best known for his eyewitness account of the Norman sack of Thessalonica in 1185 and for his extensive commentaries on Homer's Iliad and Odyssey. He is venerated as a saint in the Eastern Orthodox Church.
Eustathius wrote On the Capture of Thessalonica, an eyewitness account of the Norman siege ordered by William II of Sicily in 1185. The memoir also covers political events in Constantinople from the death of Manuel I through the usurpation of Andronikos I. It has been translated into English, Italian, French, and German by modern scholars.
Eustathius drew on works by Alexandrian grammarians and critics, including Aristarchos of Samothrace and Zenodotos, some of which are now entirely lost. His commentaries on the Iliad and Odyssey therefore preserve ancient scholarship that survives nowhere else. The definitive modern edition, by M. van der Valk, began publication in 1971.
Eustathius was officially canonized on the 10th of June 1988. His feast day in the Eastern Orthodox Church is the 20th of September.
Eustathius was a supporter of emperor Manuel I Komnenos and praised Manuel I for abolishing slavery in 1167. He was an original thinker who sometimes championed secular values such as military prowess, an unusual stance for an archbishop of his era.
Manuscripts of the funeral orations written by Euthymius and Michael Choniates, which are the main biographical accounts of Eustathius, survive in the Bodleian Library at the University of Oxford. Niketas Choniates also praised Eustathius in his own writings as the most learned man of his age.