Complex sentence: On line 32, Ongentheow is mentioned and he reappears in the later epic poem "Beowulf", which was composed sometime in 8th, 9th and the 10th centuries.
Split into simpler sentences: On line 32, Ongentheow is mentioned and he reappears in the later epic poem "Beowulf". Beowulf is the second source and it was composed sometime in 8th, 9th and the 10th centuries.