He was a pioneer in the translation of ancient Greek and Arabic medical texts by such authors as Galen and Hippocrates into Latin.

Leoniceno's stand against Pliny's work caught the attention of Angelo Poliziano, the Florentine court humanist.

Poliziano engaged Pandolfo Collenuccio, a lawyer and historian to defend Pliny against the accusations of Leoniceno.

In 1492, Leoniceno published an article entitled De Plinii et plurium aliorum medicorum in medicina erroribus.

In this treatise, he "pointed out errors in the medical portions of Pliny as well as in the works of 'barbarian' (that is, medieval Arab) physicians.

"[1] This publication was followed almost immediately by a response from Collenuccio, Pliniana defensio adversus Nicolai Leoniceni accusationem, published in 1493.

[1] Between 1492 and 1509, Leoniceno and Collenuccio published a series of pamphlets in which they argued the relative merits of the ancient sources.

While Barbaro's study resolved the philological issues, there was still the question of how to approach the contradictions that translation errors produced.

Leoniceno maintained that if Pliny was found to be in error, one should examine the texts of Theophrastus and Dioscorides rather than medieval Arab writers such as Avicenna.

In addition to translation errors, early modern naturalists were faced with the dilemma of ensuring that they were identifying plants correctly.

He still remained focused on verifying existing information rather than expanding the lists of plants found in standard texts.

Leoniceno's library was most impressive, and its contents reflected the textual approach to scholarship popular at the time.