UnScramble this Word: i h e t u s h l o g?

Questions

In 1991 Battle of the Ages-Heavyweight champ ---------- Hollyfield beats 42 year old George Foreman?

In 121 Marcus ---------- 16th Roman emperor (161-80), philosopher, born.?

In 295 8th recorded ---------- passage of Halley's Comet?

In 1770 Capt ---------- arrives in New South Wales?

In 1792 France declares war on Austria, ---------- & Sardinia?