Complex sentence: The solidus was maintained essentially unaltered in weight, dimensions and purity until the 10th century, though in the Greek-speaking world during the Roman period and then in the Byzantine economy it was known as the "nomisma" (plural "nomismata").
Split into simpler sentences: The solidus was maintained essentially unaltered in weight, dimensions and purity until the 10th century. In the Greek-speaking world during the Roman period and then in the Byzantine economy the solidus was known as the "nomisma" (plural "nomismata").