The proposed amendments were: The most serious constitutional problem the newly-established Republic of Cyprus faced in daily politics stemmed from an issue regarding municipalities; Turkish Cypriots strove for the creation of separate municipalities for Greeks and Turks, while Greek Cypriots aimed for mixed ones.
[1] Makarios took into consideration the probability of changing the constitution unilaterally; despite being warned of constitutional collapse by his own cabinet minister Glafkos Clerides (who later became the 4th president of Cyprus), Greece's foreign minister Evangelos Averoff, and the Turkish government, Makarios proceeded with the changes.
[2] He calculated the political instability of Turkey and Greece, and believed that his proposal would be backed by the United Nations.
Having been proposed after two years of peace between the two groups, the amendments and their rejection sparked a crisis between Greek and Turkish Cypriots that led to widespread intercommunal violence and culminated in the Bloody Christmas conflict.
[6] In 1966, the amendments were revealed to be part of Makarios' secret Akritas plan, with the end goal of weakening Turkish Cypriot representation in the government of Cyprus to make union with Greece easier.