Considering a source like Machiavelli's Prince, what were the main political developments and religious developments during this time period?
At the time of Machiavelli's writing, Italy was divided into a number of city states, primarily Florence, Venice, the Papal States, and the Kingdom of Naples. Each had its own government, and often quarreled or even warred with the others. Machiavelli was a citizen of Florence, which had been ruled by the wealthy DeMedici family; however that family's leaders had been exiled. During their exile, Machiavelli became an influential government employee. He served as Chancellor, and later as secretary to the War Department, commonly called the Council of Ten. When the DeMedici returned to power, Machiavelli not only lost his government position, he was (perhaps unfairly) considered an enemy of the DeMedici family. As a result, he was imprisoned and tortured.
The DeMedici were so powerful and influential that two of them were elected Pope, one of whom was Giovanni DeMedici, who took the name Leo X. Leo was the last Pope who had not previously served as a Priest. He made his mark on history by commissioning the sale of indulgences to pay for the erection of the church of St. Peter in Rome. His commission was opposed by Martin Luther, whose protest was the beginning of the Protestant Reformation. Leo had his share of faults, in fact he once commented in a letter:
God has given us the Papacy, let us enjoy it.
He also seems to have had deviant tendencies, as indicated by a quote from one of his historians after his death:
He was afterwards discovered to be exceedingly devoted - and every day with less and less shame - to that kind of pleasure that for honour's sake may not be named.
For all his faults, Leo had some pity for Machiavelli and at his urging, the latter was released from prison. Machiavelli spent the rest of his days writing, including The Prince. Most historians believe The Prince was an attempt by Machiavelli to flatter the DeMedici and get back in their good graces. He did seem to support the idea that humans were not basically good, and that a ruler (such as the DeMedici) should take any steps necessary to retain power:
For a man who, in all respects, will carry out only his professions of good, will be apt to be ruined amongst so many who are evil. A prince therefore who desires to maintain himself must learn to be not always good, but to be so or not as necessity may require.