Convert from rotl, rotel, rottle, ratel [Arab] to pond [Dutch]

Unit Definition (rotl, rotel, rottle, ratel [Arab])
The rotl, rotel, rottle, ratel is a traditional Arab unit of weight corresponding to the Roman libra, the French livre, and the English pound. There was considerable variation in the unit from time to time and from place to place, but usually the rotl was about 0.9-1.15 pound (450-530 grams). However, in some areas of the Near East, such as Syria and Palestine, larger rotls of 5.5 to 6 pounds (2.5-2.8 kilograms) were used. This unit has many spellings in European languages.

Unit Definition (pond [Dutch])
The pond is the Dutch pound, historically about 494 grams (1.089 English pounds). This unit was also used in the former Dutch Indies (now Indonesia) and throughout Southeast Asia. In the Netherlands, the pond has been reinterpreted now as a metric unit equal to exactly 500 grams (1.1023 pounds), like the German pfund.