Pliny the Elder [1st century CE] (Natural History, Book 9, 59): We are informed that there are three kinds of sponge [spongearum]: a thick and very hard and rough one is called goat-thorn sponge, a less thick and softer one called loose-sponge, and a thin one of close texture, used for making paint-brushes, the Achilles sponge. They all grow on rocks, and feed on shells, fish and mud. These creatures manifestly possess intelligence, because when they are aware of a sponge gatherer they contract and make it much more difficult to detach them. They do the same when much beaten by the waves. The tiny shells found inside them clearly show that they live by eating food. It is said that in the neighborhood of Torone they can be fed on these shell-fish even after they have been pulled off the rocks, and that fresh sponges grow again on the rocks from the roots left there; also the color of blood remains on them, especially on the African ones that grow on the Sandbanks. Very large but very soft thin sponges grow round Lycia, though those in deep and calm water are softer; the rough kind grows in the Dardanelles, and the close-textured round Cape Malea. Sponges decay in sunny places, and consequently the best are found in deep pools. Live sponges have the same blackish color as sponges in use have when wet. They do not cling to the rock with a particular part nor with their entire surface, for they have certain empty tubes, about four or five in number, running through them, through which it is believed that they take their food. They also have other tubes, but these are closed at the upper end; and it is understood that there is a sort of thin skin on the under side of their roots. It is established that they live a long time. The worst of all the species of sponge is one called in Greek the dirty sponge, because it cannot be cleaned; it contains large tubes, and the rest of it is of a very close texture. - [Rackham translation]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 6:60-62): [Book 12, 6:60] Sponges [sfungia] are named from ‘tidying’ [fingere], that is, polishing and cleaning. ... That the sponge is an animal is shown by its blood clinging to the rocks. Hence also, when it is cut, it bleeds. [Book 12, 6:61] ...some sponges are said to be male, because their openings are small and more tightly packed, and others female, because they have larger, continuous openings. Some are harder... and we can call them hircosa [“goatish”] on account of their roughness. [Book 12, 6:62] The softest kind of sponge is called penicillus because they are good for swellings of the eyes and for cleaning away rheum. Sponges are made white with special treatment, for during the summer they are spread out in the sun, and like Punic wax they absorb whiteness. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Fish 7.73): Sponges [spongie], as Pliny says, grow in the sea on rocks and cliffs. They feed on shells or fish or mud. It appears that they have understanding because when they feel themselves torn away, they contract to make it much more difficult to uproot them; they do the same thing in the flow of waves. They are also said to re-grow from the roots that have been uprooted. They rot in sunny places, so they live best in deep pools. - [Badke translation/paraphrase]