This Apology does not mean saying, “I’m sorry.” It’s more like the opposite of that.
Lutheran princes and theologians had answered the Holy Roman Emperor’s summons to explain their teaching. Six weeks after the Lutheran princes submitted their response, the Augsburg Confession, Emperor Charles V rejected it and accepted the Catholic Confutation instead. After seven more weeks of discussion, he had not only “ordered our [Lutheran] princes to accept the Confutation” (Preface to the Apology), but he refused to let them even read a written copy of the document. The talks ended.
If there had been an open door for concord, that door had now been closed. Rhetoric became intensely polemic: “The opponents are clearly deaf,” (Article IV) or “The adversaries are very stupid” (Article V1).
Within a year Melanchthon had published both the Augsburg Confession and its doubly expanded sequel, the Apology of the Augsburg Confession. Geopolitical strife would forestall further debate more than a decade, until war helped return Lutheranism to the Holy Roman Empire’s high priorities.