Pliny: Natural History, Vol. IV

to the Kings of Persia, the Ethiopians paid a hundred logs of its wood every third year, along with gold and ivory.
18 Nor should it be omitted that, as that author indicated, the Ethiopians were accustomed to pay twenty large elephant tusks for the same reason. So high was the authority of ivory in the 310th year of our city: for that author composed his history at Thurii in Italy at that time, which makes it all the more surprising that we believe the same man who had seen the river Po, which no one had seen up to that time from Asia or Greece.
19 The knowledge of the geography of Ethiopia, as we have said, which was lately brought to the Emperor Nero, taught that over 996 miles from Syene, the frontier of the empire, to Meroe, the tree is rare and none exist except those of the palm species. For this reason, perhaps, ebony was the third item in the matter of tribute.
20 IX. Pompey the Great exhibited it at Rome in his triumph over Mithridates. Fabianus denies that it can be lit, though it burns with a pleasant scent. There are two kinds: the rare one, which is the better, is arboreal, with a smooth and knotless substance of a black splendor, and is immediately pleasing even without art; the other is shrub-like, like the cytisus, and is dispersed throughout all of India.
21 X. There is also a thorn there, similar but easily detected, because when brought near lamps, the flame immediately shines through it.