that his explanation of the
heavens should be presented as the theory that it was and not as an
absolute doctrine of science.

Toward the end of the sixteenth century the necessity for the
correction of the calendar became more urgently manifest and Pope
Gregory XIII invited Father Clavius, S.J., to take up the subject. At
this time also, as is described by Pope Leo XIII in his _Motu Proprio_
of 1891, "Gregory XIII [nearly half a century before the condemnation
of Galileo] ordered a tower to be erected in a convenient part of the
Vatican buildings and to be fitted out with {475} the greatest and
best instruments of the time. There he held the meetings of the
learned men to whom the reform of the calendar had been entrusted. The
tower stands to this day a witness to the munificence of its founder.
It contains a meridian line by Ignazio Danti of Perugia, with a round
marble plate in the centre, adorned with scientific designs. When
touched by the rays of the sun that are allowed to enter from above,
the designs demonstrate the error of the old reckoning and the
correctness of the reform." It was evidently the intention of the Pope
that there should be, as a permanent institution in Rome, an
astronomical observatory fully equipped and supported by the revenues
of the Holy See and with a prominent scientist at its head. This
purpose has been constantly kept in mind by the Popes ever since,
though not long after Gregory's time, but not at all because of any
opposition to science, the observatory founded by him came for more
than a century not to be used for the purpose intended because its
place was supplied by another Roman institution directly under the
patronage of the Popes.

This was the Roman College, the great central school of the Jesuits,
in the capital of Christendom. That Order was scarcely fifty years in
existence in Pope Gregory XIII's time, yet it was to a member of it
that the Pope turned for expert scientific direction in the correction
of the calendar. During the next three centuries science as patronized
by the Popes in Rome was mainly in the hands of the Jesuits. When it
is recalled that this Order is directly under the control of the Pope,
the professed members taking a special vow of obedience to him, it
will be understood that the Jesuit policy with regard to science must
be taken as representing the Papal position in its regard. If it is
further recalled that Poggendorff in his Biographical Lexicon o