Choose the correct tense form from the given options. This was the first time…

Answer: Past Perfect.

Rule: Use past perfect to describe an action that was completed before another past moment or reference point.

• Identify the past reference: "This was the first time" sets a past reference point.

• Place the earlier action in past perfect: the king's loss happened before that past reference, so use "had lost."

Why the other tense forms are not suitable:

• Past indefinite (simple past): "lost" states a past event but does not show it occurred before the past reference point.

• Past continuous: "was losing" implies an ongoing action, while the sentence speaks of a completed single event.

• Past perfect continuous: "had been losing" indicates a continuous action before a past moment; the context calls for a completed action, so simple past perfect is better.

Final sentence: This was the first time the mighty king had lost a battle.