How did pepin iii prove his rule was legitimate? why did people accept this?

pepin the short[a] (german: pippin der kurze, french: pépin le bref, c. 714 – 24 september 768) was the king of the franks from 751 until his death. he was the first of the carolingians to become king.[b][2]

the younger son of the frankish prince charles martel and his wife rotrude, pepin's upbringing was distinguished by the ecclesiastical education he had received from the monks of st. denis. succeeding his father as the mayor of the palace in 741, pepin reigned over francia jointly with his elder brother carloman. pepin ruled in neustria, burgundy, and provence, while his brother carloman established himself in austrasia, alemannia and thuringia. the brothers were active in suppressing revolts led by the bavarians, aquitanians, saxons, and the alemanni in the early years of their reign. in 743, they ended the frankish interregnum by choosing childeric iii, who was to be the last merovingian monarch, as figurehead king of the franks.

the articles of confederation only set up the continental congress at the federal level. there were no executive or judicial branches except within the states. the states were allowed to keep every right that was not specifically given to congress. the bonding of the states was through a 'firm league of friendship' that best served as a defense agreement against invasion. states were not allowed to use taxes as a way to discourage treaties, and states were extremely limited in their dealings with foreign nations.

not many historians today talk about the strengths of the articles of confederation, likely because of how unpopular the document quickly became. the articles did set the legislative body, congress, as the highest power in the nation because of the fear of monarchy. congress had the sole power to declare war, assign treaties, entertain foreign relations, and operate post offices. disputes between states and territorial issues were to be brought to congress. the document also stipulated that canada was allowed to enter the union if they desired.

there were more weaknesses than strengths under the articles of confederation. the lack of power given to the continental congress strangled the federal government. the articles gave congress the power to pass laws but no power to enforce those laws. if a state did not support a federal law, that state could simply ignore it. congress had no power to levy taxes or regulate trade. without a federal court system or executive leader, there would be no way to enforce these laws, either. amending the articles of confederation would also require a unanimous decision, which would be extremely difficult.

the answer is use of support