On that day Admiral Herbert, disguised as a blue-jacket, left with the invitation to the Prince of Orange to come over. It was written by Algernon Sidney's brother, and bore the signatures of seven considerable men, who were prepared to risk their lives. Several others acquiesced, and it was not the act of one party. The thing had become inevitable when the prince was born. It was delayed until the issue was decided between the crown and the Church. The associates assured William that the Prince of Wales was an imposture, and that he must come, in order to secure his own birthright, as well as the liberties of England. William of Orange had not intrigued that the crown should pass to his wife before the time, and had given his uncle much good advice. For him it was everything that England should not be against him in the struggle with Lewis XIV. For that, he had the Habsburgs on his side, and it was essential that they should still be with him if he obeyed the call of his friends. He had been preparing for it ever since he sent Dykvelt over in 1687, and had asked the States of Holland to hold twenty-five men-of-war and 9000 sailors in readiness, to meet the danger which threatened from France. James took alarm, and warned William that the succession was not absolutely safe. Lewis, who much dreaded the prospect of having his ablest and most formidable enemy at Whitehall, wished the Princess Anne to precede her elder sister. To strengthen her claim with her father he proposed that she should become a Catholic, and sent over books of controversy for that purpose. James, on the other hand, told William that there would be no crown to inherit, but a commonwealth in England, if he did not succeed in his endeavour to make himself master. Dykvelt had conducted the secret negotiation which ended in the invitation of 30th June.