king this step; it was not an act of pure opportunism. His early
Catholicism had probably been little more than an outward profession,
and as soon as he began to think seriously about religious questions,
his natural bent had led him first to the Lutheran faith of his family,
and then to the sterner doctrines, which had gained so firm a foothold
in the towns of Holland and Zeeland. Nevertheless William, though
henceforth a consistent Calvinist, was remarkable among his
contemporaries for the principles of religious toleration he both
inculcated and practised. He was constitutionally averse to religious
persecution in any form, and by the zealots of his party he was
denounced as lukewarm; but throughout his life he upheld the right of
the individual, who was peaceful and law-abiding, to liberty of opinion
and freedom of worship.

The year 1574 opened favourably. By a remarkable feat of arms the
veteran Spanish commander Mondragon had, October, 1572, reconquered
several of the Zeeland islands. His men on one occasion at ebb-tide
marched across the channel which lies between South Beveland and the
mainland, the water reaching up to their necks. The patriot forces had
since then recovered much of the lost ground, but Middelburg was
strongly held, and so long as the Spaniards had command of the sea, was
the key to the possession of Zeeland. On January 29, 1574, the
Sea-Beggars under Boisot attacked the Spanish fleet near Roemerswaal and
after a bloody encounter gained a complete victory. The siege of
Middelburg was now pressed and Mondragon surrendered, February 18. The
prince at once set to work to create a patriot government in the
province. Four towns had representatives, Middelburg, Zierikzee, Veere
and Flushing. William himself acquired by purchase the marquisate of
Flushing and thus was able to exercise a preponderating influence in the
Provincial Estates, all of whose members were required to be Calvinists
and supporters of the rebel cause.

The investment of Leyden by the Spaniards threatened however, now
that Haarlem had fallen, to isolate South Holland and Zeeland; and
William did not feel himself strong enough to make any serious attempt
to raise the siege. Lewis of Nassau therefore, with the help of French
money, set himself to work with his usual enthusiastic energy to
collect a force in the Rhineland with which to invade the Netherlands
from the east and effect a diversion. At the head of 7000 foot and
3000 h