Complex sentence: This didn't happen, and it appears that Glyndwr, at the time fighting in Carmarthenshire, was unaware that Hotspur has acted although it appears some Welsh forces from the Cheshire borders may have joined him.
Split into simpler sentences: This didn't happen, and it appears that Glyndwr, at the time fighting in Carmarthenshire, was unaware that Hotspur had acted. Although it appears some Welsh forces from the Cheshire borders may have joined him.