to the time of his leaving Hveen, though even then he had not completed
his programme. About the time that King Christian reached the age of
eighteen, Tycho began to look about for a new patron, and to consider
the prospects offered by transferring himself with his instruments and
activities to the patronage of the Emperor Rudolph II. In 1597, when
even his pension from the Royal treasury was cut off, he hurriedly
packed up his instruments and library, and after a few weeks' sojourn at
Copenhagen, proceeded to Rostock, in Mecklenburg, whence he sent an
appeal to King Christian. It is possible that had he done this before
leaving Hveen it might have had more effect, but it can be readily seen
from the tone of the king's unfavourable reply that his departure was
regarded as an aggravation of previous shortcomings. Driven from Rostock
by the plague, Tycho settled temporarily at Wandsbeck, in Holstein, but
towards the end of 1598 set out to meet the Emperor at Prague. Once
more plague intervened and he spent some time at Dresden, afterwards
going to Wittenberg for the winter. He ultimately reached Prague in
June, 1599. Rudolph granted him a salary of at least 3000 florins,
promising also to settle on him the first hereditary estate that should
lapse to the Crown. He offered, moreover, the choice between three
castles outside Prague, of which Tycho chose Benatek. There he set about
altering the buildings in readiness for his instruments, for which he
sent to Uraniborg. Before they reached him, after many vexatious delays,
he had given up waiting for the funds promised for his building
expenses, and removed from Benatek to Prague. It was during this
interval that after considerable negotiation, Kepler, who had been in
correspondence with Tycho, consented to join him as an assistant.
Another assistant, Longomontanus, who had been with Tycho at Uraniborg,
was finding difficulty with the long series of Mars observations, and it
was arranged that he should transfer his energies to the lunar
observations, leaving those of Mars for Kepler. Before very much could