The son of a Sub-Treasurer of the Queen's Household, Mathias studied at Kingston, Surrey and Trinity College Cambridge (B.A. 1774, Fellow, 1776, M.A. 1777). He held his father's position at court and was librarian at Buckingham Palace (1812); he was F.S.A. and F.R.S. (1795). Mathias's anonymously published satire on men of letters, Pursuits of Literature (1794) went through sixteen editions. He retired to Italy in 1817 and published a number of works in Italian, including translations of Spenser. George IV awarded Mathias a pension.
Qua quis ratione seipsum citra invidiam laudare possit. 1775.
Utrum imperium atque artes humaniores occidentali cursue nationibus sese deterant. 1776.
An heroic address in prose to the Rev. R. Watson. 1780.
An heroic epistle to the Rev. Richard Watson. 1780.
Runic odes imitated from the Norse tongue in the manner of Mr Gray. 1781.
An essay on the evidence relating to the poems attributed to Rowley. 1783.
Odes English and Latin. 1790.
Honoratissimo viro, T. Orde. 1791.
The imperial epistle from Kien Long to George the Third. 1795?
The pursuits of literature: a satirical poem in dialogue. 1794, etc.
The political dramatist of the House of Commons. 1795.
Villae Formianae, oden. 1795.
An epistle in verse to the Earl of Jersey. 1796.
An equestrian epistle in verse to the Earl of Jersey. 1796.
An appendix to the two epistles in verse containing the whole of the correspondence. 1796.
A letter to Buckingham on the emigrant French priests. 1796.
An address to William Pitt. 1797.
The grove: a satire. 1798.
A letter to the author of Remarks on the Pursuits of literature. 1798.
The shade of Pope on the banks of the Thames. 1798.
A translation of the passages quoted in the Pursuits of literature. 1798.
Works of the author of The pursuits of literature. 1799.
Pandolphe attonito!: or Lord Galloway's poetical lamentation. 1800.
Poems on various occasions collected from the newspapers. 1801.
Componimenti lirici de pia illustri poeti d'Italia [ed. Mathias]. 3 vols, 1803.
A letter occasioned by the death of Nicholls with an Italian ode. 1809.
Odae latinae. 1810.
The works of Gray. 2 vols, 1814.
Observations on the writings and character of Mr. Gray. 1815.
Lyrica sacra. 1818.
Il cavaliero della croce rossa ... recato in verso italiano. 1826.
La mutabilita ... recato in verso italiano. 1827.
Poemata latina. 1832.