At least three of the problems must be originals; the remaining may have been published before.
E. L. Lequesne, S. Loyd, [S.] Rosenthal
S. Loyd was both a judge and a competitor in the problem tourney. As he also won a prize, it would have been desirable to know how his set was judged. No such information has been found.
The congress book content was published in parts, which were sent to subscribers as they were printed. According to The Era 1868-07-05 the part that concerned the problem tourney had, to the chess editor's knowledge, not yet been published.
In the chess column of The Era, 1867-08-04, the following communication from a pseudonymous contributor was printed:
The chief event since the finish of the Tourney has been the decision as to the prizes for Problems. The Committee appointed to examine the competing sets was to consist, I am told, of the four winners of the Tournament for the Emperor’s prize, but they fell to squabbling, and three of them declined to act. Finally, I believe, the examination devolved on Kolisch and the young English player, De Vere, who were said to have executed their very onerous task with skill and impartiality. The result of their labours has not transpired.As the names of the judges were published already in the congress announcement, the account is probably a misunderstanding, at least partially.
The congress book did mention that the Problem Committee decided that the prize-winning problems should be submitted to additional verification by the four winners of the Grand Tournament. It did not say anything more about the details of this activity except that the result agreed with that of the problem tourney judges. This may be the origin of the passage quoted above.
The initial of judge Rosenthal is not given in the sources; on the assumption that they are the same person, it has been supplied from the information about the player S. Rosenthal who participated in the congress game tournament.
Problems known to not be originals are indicated with a
1 Prize: C. Bayer
Key: 1. Qa5
Source: Schachzeitung, v. 18, i. 10 (Oct.-Nov. 1863), p. 349, prb. 1667
Key: 1. Nd6
Source: Congrès International des Échecs, p. 347, prb. I:2
2 pr. set, Le Palamède Français, 1865
Key: 1. Sg3
Source: Le Palamède Français, v. 2, i. 13 (Sept. 1865), p. 44, prb. 88
Key: 1. Be2
Source: Congrès International des Échecs, p. 349, prb. I:4
1 pr. set, British Chess Association, 1862 (London)
Key: 1. Ng×f4
Source: The Era, v. 25, i. 1263 (1862-12-07), p. 5, prb. 440
2 Prize: S. Loyd
Key: 1. Ba8
Source: Cincinnati Dispatch, (1858-09-05), prb. 45
Key: 1. b×a8=N
Source: Congrès International des Échecs, p. 351, prb. II:2
Key: 1. Qa8
Source: Congrès International des Échecs, p. 353, prb. II:3
Key: 1. B×a6
Source: Congrès International des Échecs, p. 353, prb. II:4
The Excelsior problem.
Key: 1. b4
Source: The Era, v. 29, i. 1501 (1861-01-13), p. 14, prb. 337
3 Prize: E. Grosdemange
Key: 1. Bc1
Source: Congrès International des Échecs, p. 355, prb. III:1
Key: 1. Rc2
Source: Congrès International des Échecs, p. 355, prb. III:2
[+] = Faulty: No solution
Key: 1. Ra5
Source: Congrès International des Échecs, p. 355, prb. III:3
Key: 1. Ne4
Source: La Nouvelle Régence, v. 5, i. 3 (Mar. 1864), p. 95, prb. 237
Key: 1. Rh1
Source: La (Nouvelle) Régence, v. 1, i. 10 (Oct. 1860), p. 320, prb. 40
Key: 1. Bg4
Source: Le Sphinx, v. 1, i. 18-19 (1-15 Jan. 1866), p. 300, prb. 67