In 1677, therefore, Penn again sailed for Holland with George Fox, Robert Barclay, and George Keith, all prominent members of the Society of Friends, in a vessel the captain of which had served under Admiral Penn. Rotterdam, Leyden, Haarlem, and Amsterdam were visited in succession and large meetings held, there being many Quakers in each of these cities. At Amsterdam George Fox was left behind to attend a general assembly or conclave, where questions of importance to the Society were to be settled, while Penn and his other two companions went on to Herford. They were most kindly received by the Princess Elizabeth, who not only permitted them to hold several public meetings, but also invited them frequently to her own apartments for religious converse, owing to which she finally became a member of the sect herself. Robert Barclay now returned to Amsterdam to join Fox, but Penn, accompanied by Keith, who was almost as proficient as himself in the German language, journeyed on by way of Paderborn and Cassel to Frankfort-on-the-Main, where Penn preached with great effect, winning over many influential persons to his own belief. From Frankfort the two Quaker apostles went up along the Rhine to Griesheim near Worms, where a small Quaker community had been formed. Here Penn’s plan for founding a trans-atlantic State for the free worship of their religion was received with the greatest enthusiasm, and large numbers did indeed afterward emigrate to New Jersey, where they took an important place in the colony, being among the first to condemn and abolish the slavery then existing in America, and established a reputation for German worth and integrity beyond the seas. On his return to Cologne, Penn found a letter from the Princess Elizabeth urging him to go to Mühlheim to visit the Countess of Falkenstein, of whose piety she had already told him. In endeavoring to carry out this request of his royal patroness, however, Penn and his friend met with a misadventure. At the gates of the castle they encountered the Countess’ father, a rough, harsh man with small respect for religion of any sort. He roundly abused them for not taking off their hats to him, and on learning that they were Quakers, he had them taken into custody and escorted beyond the boundaries of his estates by a guard. Here they were left alone in the darkness, at the edge of a great forest, not knowing where they were or which way to turn. After much wandering about they finally reached the town of Duisburg, but the gates were closed and in spite of the lateness of the season they were forced to remain outside till morning.