He soon found a bigger man than Ives to argue with, for as he traveled through Oxfordshire preaching the Quaker cause he came to the University of Oxford, where he had been a student, and learned that the young men there who were interested in Quakerism were treated worse than ever. The Vice Chancellor of Oxford thought that the Quakers might become a dangerous political party, and was doing all in his power to abolish the new religion. Penn wrote him a letter in which, with fiery ardor, he denounced the Vice Chancellor for his persecution of Quaker students, and followed it up with other broadsides of attack on all who held similar views. He was a militant character, and when he argued before a public meeting, or wrote a letter that was to be read by his opponents, he never hesitated to express himself as strongly as he knew how. So in his letter to the Vice Chancellor he gave himself free rein. He wrote: "Shall the multiplied oppressions which thou continuest to heap upon innocent English people for their peaceable religious meetings pass unregarded by the Eternal God? Dost thou think to escape his fierce wrath and dreadful vengeance for thy ungodly and illegal persecution of his poor children? I tell thee, no. Better were it for thee hadst thou never been born. Poor mushroom, wilt thou war against the Lord, and lift up thyself in battle against the Almighty? Canst thou frustrate his holy purposes, and bring his determination to nought? He has decreed to exalt himself by us, and to propagate his gospel to the ends of the earth." Fine, spirited words are these, worthy of the valiant courage of young William Penn! Penn returned from Oxfordshire to London, and went one day to a meeting in Wheeler Street. He started to address the meeting, but no sooner had he begun than a sergeant marched in with a file of soldiers, dragged him from the platform, and carried him off to the Tower. That evening an officer and some musketeers marched him from the Tower to Sir John Robinson, the lieutenant, who asked him many questions, trying to make it appear that Penn was a dangerous man, who, unless he were checked, might turn out to be another Cromwell. Sir John, knowing that the Quakers were opposed to all oaths, called on Penn to swear that he would never take up arms against the king, and also to take a solemn oath that he would never try to make any change of government either in church or state. This oath Penn refused to take, saying that the Quakers were opposed to all fighting as well as oath-taking. "If I cannot fight against any man (much less against the king)," said he, "what need I to take an oath not to do it? Should I swear not to do what is already against my conscience to do?"