Janissary Corps: From Loyalty to Mutiny

"In theory these corps (the Janissaries) were the servants of the sultan but in reality he was the prisoner of their whims, and without their support he could not exercise his sovereignty," (Osman's Dream, 153.)
Throughout our lectures in class (both MME and Ottoman Empire) I continue to find the Janissaries such an interesting topic of discussion. From why they were created, to how they rose with, at first, loyalty, and how they declined with mutiny. What sparks my interest most is how they rose with a strong sense of loyalty to the sultan and as the time of the Janissaries began to decline (alongside the "decline" of the Ottoman Empire) it seems this decline is a result of their mutiny. Their mutiny is what immediately frightened the sultan and forced him to act spontaneously and with unfortunate and rash decisions. I hope we discuss this much further in our lectures because now what I understand of the Janissaries is that they emerged as this "new" army filled with men who "replace love of family.. with.. fanatical obedience, lust for spoils.. denying that their was any 'nobility of motive' behind their military successes," (The Janissaries, 3.) As the numbers of Janissaries throughout the Empire grew, they became local elites, began to develop local patriotism and then quickly making their own, subtle demands. For instance, the Janissaries were create to extend Ottoman control, but "they soon insisted on taking part in the profitable business of naval warfare," (The Janissaries, 45) from then on more insistences would only occur. Now I'm not sure if their insistence with the naval warfare is a valid example of when they first began to lose sight of their loyalty, but it seems fair to say that. (If you disagree let me know and why.. that would be helpful to me!!) In Osman's Dream, chapter 6 (page 152) describes actual instances of Janissary mutiny, in some cases these janissaries would bar the gates of the Topkapi Palace against the Sultan. So far I understand that the mutiny was some result concerning their pay..? For now I'm counting on the causes and results to be cleared up in the near future (lectures, or reading assignments, or comments! please) I definitely want to further look the reality of their loyalty, if it existed and when, and then why it diminished..