One of the main critiques was directed at the sale of indulgences, which referred to the practice of granting remission of sins or shortening of time in purgatory in exchange for financial contributions. Luther argued that this practice contradicted the idea of salvation through faith alone, as it suggested that one could purchase forgiveness for sins rather than relying solely on God's grace.
Luther also criticized the Church's emphasis on the authority of the Pope and the hierarchy of the Catholic Church, arguing that the Bible should be the sole authority in matters of faith. He proposed the concept of the priesthood of all believers, asserting that every individual had direct access to God through faith, without the need for intermediaries such as priests or the Pope.
Criticisms were also directed at the practice of clerical celibacy and the accumulation of wealth and political power by the Church. Some reformers argued for a simpler, more spiritual approach to Christianity, rejecting the elaborate ceremonies and rituals that had become prevalent in the Catholic Church.
It was these critiques and calls for reform that led to the establishment of the first main Protestant religion, Lutheranism. Luther's Ninety-Five Theses, published in 1517, sparked a religious movement that spread across Europe and eventually led to the formation of Protestant churches that broke away from the authority of the Catholic Church.
In summary, the Catholic Church's practices, particularly the sale of indulgences, the emphasis on papal authority, clerical celibacy, and the accumulation of wealth and power, were the main subjects of critique that led to the establishment of the first main Protestant religion, Lutheranism. These critiques challenged fundamental aspects of Catholic theology and practices, ultimately resulting in the Protestant Reformation and the emergence of various Protestant denominations.