Newgate Street, where, previously to the great fire of London, there was a monument to his memory, with a Latin inscription preserved by Weaver (Funerall Monuments, p. 391).
He married, first, Margaret, daughter of Sir John Clere of Ormesby, Norfolk, by whom he had a son, Clere Haddon, who was drowned in the river Cam, probably in 1571; and secondly, Anne, daughter of Sir Henry Sutton, who survived him, and remarried Sir Henry Cobham, whom she also survived.
Queen Elizabeth being asked whether she preferred Buchanan or Haddon, adroitly replied, 'Buchannum omnibus antepono, Haddonem nemini postpono.' In his own day unqualified encomiums were bestowed on his latinity. Hallam, however, remarks of his orations: 'They seem hardly to deserve any high praise. Haddon had certainly laboured at an imitation of Cicero, but without catching his manner or getting rid of the florid, semi-poetical tone of the fourth century.' Of the 'Reformatio Legum Ecclesiasticarum,' the work of Haddon and Cheke, Hallam says: 'It is, considering the subject, in very good language' (Literature of Europe, i. 501, 502). Apparently Haddon was not very courtly in his manners. On coming into Queen Elizabeth's presence her majesty told him that his new boots stunk. He replied: 'I believe, madam, it is not my new boots which stink, but the old petitions which have been so long in my bag unopened.'
Subjoined is a list of his works; 1. 'Epistola de Vita et Obitu Henrici et Caroli Brandoni, Fratrum Suffolciensium,' London, 1551, 4to. 2. 'Cantabrigienses: siue Exhortatio ad literas,' London (Richard Grafton), 1552, 12mo. This was furtively sent to the press by Thomas Wilson, afterwards knighted, who, in his dedication to John Dudley, earl of Warwick, says the theft was a 'pium facinus.' The work is reprinted in 'Lucubrationes.' 3. 'Oratio Jesu Christi Salvatoris nostri qua Populum affatus est cum ascendisset Montem. Item, Epistola Sancti Jacobi. Ad hæc Psalmus Davidis centesimus tertius. Omnia hæc comprehensa versibus,' London, 1555, 8vo. Reprinted in 'Lucubrationes'. 4. 'Liber Precum Publicarum,' London, 1560, 4to. 5. 'Oratio Funebris in honorem Martini Buceri,' Strasburg, 1562, 8vo, and in 'Buceri Scripta Anglicana;' also in Sir John Cheke's 'De Obitu doctissimi et sanctissimi Theologi Doctoris M. Buceri,' London, 1551, 4to. 6. 'Gualtheri Haddoni pro Reformatione Anglicana Epistola Apologetica ad Hier. Osorium, Lusitanum,' Paris (Stephens), 1563. Reprinted in 'Lucubrationes' and in Gerdes's 'Scrinium Antiquarium, sive Miscellanea Groningana Nova,' 1752, iii. 492-522. Translated into English by Abraham Hartwell [q. v.], under the title of 'A Sight of the Portugall Pearle,' London , 16mo. A reply to Haddon, by Emanuel Dalmada, bishop of Angra, was published in Latin at Antwerp, 1566, 4to. 7. 'Lucubrationes passim collectæ et editæ: studio et labore Thomæ Hatcheri, Cantabrigiensis,' London, 1567, 4to—a collection containing, besides the oration on Bucer and many Latin letters addressed to Henry, duke of Suffolk, John, duke of Northumberland, Sir John Cheke, George Day, bishop of Chichester, provost of King's College, Cambridge, and the vice-provost and seniors of that college, Dr. Richard Cox, Dr. Thomas Wilson, Robert, earl of Leicester, Sir Thomas Heneage, and John Sturmius, the following orations: (a) 'De laudibus eloquentiæ oratio.' (b) 'In Admissione Bacchalaureorum Cantabrigiensium, Anno Domini, 1547, Oratio.' (c) 'De Laude Scientiarum oratio habita Oxoniæ.' (d) 'Oratio Theologica habita in regio collegio.' (e) 'Oratio quam habuit, cum Cantabrigiæ legum interpretationem ordiretur.' (f) 'Oratio habita Cantabrigiæ cum ibi inter alios Visitator regius versaretur.' (g)' Oratio ad pueros Ætonenses.' 8. 'Poemata, studio et labore Thomæ Hatcheri, Cantabrigiensis, sparsim collecta et edita,' London, 1567,4to. 9. 'Reformatio Legum Ecclesiasticarum ex Authoritate primum Henrici 8 inchoata: deinde per Regem Edouardum 6 prouecta, adauctaque in hunc Modum, atque nunc ad pleniorem ipsarum Reformationem,' London, 1571,4to. Translated into Latin by Haddon and Sir John Cheke. 10. 'Poematum sparsim collectorum Libri duo,' London, 1576, 12mo. In this work, which is of extreme rarity, there are some pieces not included in the collection of 1567; also poems on Haddon's death. Wood mentions a very doubtful edition, London, 1592, 8vo. 11. 'Contra Hieron. Osorium, ejusque odiosas insectationes pro Evangelicæ veritatis necessaria Defensione, Responsio Apologetica. Per clariss, virum Gualt. Haddonum inchoata: Deinde suscepta et continuata per Joan. Foxum,' London, 1577, 4to. An English translation by James Bell appeared at London, 1581, 4to, and is reprinted in vol. viii. of the 'Fathers of the English Church,' edited by the Rev. Legh Richmond, London, 1812, 8vo.
[Addit. MS. 5872 f. 5, 19400 ff. 86. 95, 24489 p. 508, 33271 f. 37; Ames's Typogr. Antiq. (Herbert). pp. 535, 541, 603, 605, 663, 669, 689, 698, 704, 837, 903, 946, 1610, 1624; Beloe's Anecdotes, v. 217; Biog. Brit.; Bloxam's Magd. Coll. Reg. ii. l-lvii. lxvi. 10. 320-2, iii. 101, 114, iv. pp. xxviii. 56, 77, 91n.; Churton's Life