184 Popes and Jews, 1095–1291
Book 2, also part of Canon 26 of lateran III, ruled that Christians might act as
witnesses against Jews and Muslims in legal cases.129
Two capitula of De usuris, Titulus 19 of Book 5 of the Liber extra, were con-
cerned with the particular problem of Jewish usury. Capitulum 12, an extract
from Innocent III’s decretal ‘Post miserabile’, now here with the slightly different
title, ‘Post miserabilem’, declared that secular authorities must compel Jews to
remit usury and threatened excommunication of Christians who consorted with
usurious Jews:130
(Indeed) we order that the Jews shall be forced by you, my sons the princes, and by the
secular powers, to remit the usury to Christians. And until they have remitted them,
we order by sentence of excommunication that every kind of association with them by
all faithful Christians, whether in commerce or in other business, be denied.Capitulum 18 of Titulus 19 of Book 5, Quanto amplius, Constitution 67 of lateran
Iv , affirmed that Jews were to be forced to restore usurious loans extorted from
Christians and pay tithes or offerings on their possessions.131
Throughout the thirteenth century these decretals were a source of continual dis-
cussion among canon lawyers. Glossae—commentaries on the Liber extra which
gave marginal cross-references to related texts and expositions of their difficulties—
and a number of Summae, which dealt with issues of canon law more systematically
and were published independently of the texts they examined, discussed, inter alia,
the treatment of both heretics and Jews.132 of especial note was Innocent Iv’s com-
mentary on the Liber extra known as the Apparatus super quinque libris decretalium
which was never superseded.133 This commentary did not change the original
meaning of the decretals, nor make substantial additions, but explained and elabor-
ated on crucial points in the texts. Books 3 and 5 included a commentary on those
decretals of the Liber extra concerning Jews. In particular, rubric 32 of Book 3, De
conversione coniugatorum, commented on the twenty capitula of Titulus 32 of Book
3 of the Liber extra concerning marriage and the religious life,134 and included dis-
cussion of Capitulum 20 which concerned an infidel woman who had converted to
129 X.2.20.21, col. 322. See Dahan, Les Intéllectuels chrétiens et les juifs au moyen âge, p.115.
130 X.5.19.12, cols 814–15: ‘Iudaeos (vero) ad remittendas Chritianis usuras per vos, filii principes
et potestates compelli precipimus saeculares. Et, donec eis remiserint, ab universis Christi fidelibus
tam in mercemoniis quam in aliis per excommnicationis sententiam eis iubemus communionem
omnimodam denegari.’ See also with very minor word differences Innocent III, ‘Post miserablile(m)
Hierusolymitanae’ (17/15 August 1198), Grayzel, Vol. 1 , p.86; Simonsohn, p.71.
131 X.5.19.18, col. 816.
132 Clarence-Smith, Medieval Law Teachers and Writers, pp.15–16.
133 James Brundage, Medieval Canon Law (london, new York, 1995), p. 225; Clarence-Smith,
Medieval Law Teachers and Writers, pp.45–6; James Brundage, Medieval Canon Law and the Crusader
(Madison, london, 1969), p.98. For example, rubric 34 of Book 3 entitled De voto et voti redemptione
was a commentary on Titulus 34 of Book 3 of the Liber extra. See Innocent IV, Apparatus, Bk 3,
rubrica 34, pp. 176v–177v. In particular, Capitulum 8, Titulus 34 of Book 3 of the Liber extra was
concerned with the delaying and the redemption of crusade vows. See X.3.34.8–9, cols 593–4;
Innocent Iv’s commentary on this capitulum ranged far beyond this subject matter and included
much important material. See Innocent IV, Apparatus, Bk 3, rubrica 34, cap. 8, pp.176r–177v. See
Brundage, Medieval Canon Law, p.163.
134 Innocent IV, Apparatus, Bk 3, rubrica 32, caps 1–21, pp.174r–176v.