As for the claim that his head was brought before Yazīd (1), it is false, and its chain of transmission is disconnected (2).
His uncle Yazīd, a righteous man, was one of the Companions. He died during ‘Umar’s caliphate, whereupon ‘Umar appointed Mu‘āwiya in his brother’s place. ‘Umar was among those most knowledgeable about men’s character, most skilled in governance, and least swayed by personal inclinations. During his caliphate, he appointed none of his relatives to office; rather, he chose those whom he considered best suited to it. He therefore appointed Mu‘āwiya only because he considered him fit to govern.
Then, when ‘Umar died (3), ‘Uthmān expanded Mu‘āwiya’s jurisdiction until he placed all of Syria under his authority. During ‘Umar’s caliphate, Syria comprised four districts: Palestine, Damascus, Homs, and Jordan. Later, Qinnasrīn and al-‘Awāsim were separated from the district of Homs. Subsequently, Aleppo was built up and Qinnasrīn fell into ruin, while al-‘Awāsim changed hands between the Muslims and the People of the Book.
Mu‘āwiya served as governor on behalf of ‘Umar and ‘Uthmān for twenty years, then ruled for twenty years. His subjects were grateful for his conduct and benevolence and were content with him, to the point that they obeyed him even in such matters as fighting ‘Alī.
It is well known that he was better than his father, Abū Sufyān, and there were stronger grounds for considering his holding office permissible than his father’s. It therefore cannot be said that it was unlawful for him to hold office. Even if it were supposed that someone else was