Complex sentence: The temple's dedicatory inscription survives in the Vatican Museums and an enormous monolithic granite column (2m in diameter) with a white marble capital (2.12m high on its own) survives near Trajan's Column perhaps belongs to the temple.
Split into simpler sentences: The temple's dedicatory inscription survives in the Vatican Museums. An enormous monolithic granite column (2m in diameter) with a white marble capital (2.12m high on its own) survives near Trajan's Column and perhaps comes from the temple.