Possible Clues:

• The screening for the old troops of The Roman Tortoise?
• Battle-weary screen offering The Roman Tortoise?
• Roman battle formation with shields linked as one
• Note boss on round shield for centurions
• Ancient screen offering The Tortoise
• Latin for 'tortoise', also a formation of shields used as protection by Roman soldiers
• Try out posh fleece — it protected Roman soldiers
• Test you do in Rome to protect the army
• Ancient screen playing The Tortoise
• Trial complete about universal protection for soldiers