1939: Nepal's first political party "Nepal Prajaparishad" formed to revolt against Rana dynasty in Nepal by Tanka Prasad Acharya, Dharma Bhakta Mathema, Dashrath Chand, Sukra Raj Shastri, Gangalal Shrestha, Chudaprasad Sharma, Govinda Prasad Upadhya(Poudyal), Puskar Nath Upreti, Mukunda Nath Rimal, Bal Bahadur Pandey, Druba Prasad Dawade, Fadindra Nath Satyal, Hari Krishna Shrestha, Chakra Bahadur Khatri etc.
1940 Oct: Rana government arrested almost all members of the PrajaParishad.
1941 Jan 19: Rana government declared death penalty against Dharma Bhakta Mathema, Dashrath Chand, Sukra Raj Shastri and Gangalal Shrestha and jail sentences to many members. And after this PrajaParishad was effectively dissolved.
1946 Jan 25-26: "Nepali National Congress" was founded in Bhawanipur, India. Imprisoned Tanka Prasad Acharya (from Nepal Prajaparishad) elected as president and B. P. Koirala elected as acting-president.
1947 Jun 11: First ever election in Nepal held by Rana regime as in all 21 wards of Kathmandu municipality. Total 68,118 male above 21 years were eligible to vote.
1947 March 13: National Congress started nationwide demostration against Rana regime.
1947 March: BP Koirala & Girija P Koirala arrested while entering Nepal.
1948 Jan 16: Rana PM Padma Shamsher promulgated the first constitution of Nepal which would implement from 1948 Apr 1.
1948 Apr 30: Mohan Shamsher became new Rana PM as Padma Shamsher resigned.
1948 May 1: Mohan Shamsher banned new constitution and National Congress.
1948 Aug 4: "Nepali Democratic Congress" founded by Mahendra Bikram Shah.
1948 Nov: BP Koirala again arrested in Kathmandu.
1949 Sep 15: Communist Party of Nepal founded in Culcutta, India. This is the party which majority of 10+ present communist parties in Nepal claim origin from. Founding General secretory was Puspalal Shrestha and members were Nar Bahadur Karmacharya, Niranjan Govinda Baidhya and Narayan Bilas Joshi.
1950 Apr 9: "Nepali Congress" party founded merging Nepali National Congress and Nepali Democratic Congress parties. Martika Prasad Koirala became first president of the party.
1950 Sep 27/28: Convention of Nepali Congress.
1950 Nov 6: King Tribhuvan took refuse in the Indian Embassy in Kathmandu and Nepali Congress announced armed revolution in Nepal.
1950 Nov 7: PM Mohan Shamsher appointed Gyanendra as King.
1950 Nov 10: King Tribhuvan flown to Delhi with family.
1950 Nov 11-12: Congress's Mukti Sena captured Birgunj and established provisional government headed by Tej Bahadur Amatya.
1950 Nov 12: Mukti sena captured Udayapur Gadhi.
1950 Nov 13: Mukti sena led by KI Singh attacked Bhairabha.
1950 Nov 16: Mukti sena captured Rangeli.
1950 Nov 19: Mukti sena captured Haraicha.
1950 Nov 20: KI singh attacked Bhairaba second time. Gov forces recaptured Birgunj.
1950 Nov 24: Indian PM Nehru started mediation in the conflict.
1950 Dec 10-11: Mukti sena captured Dingla & Khotang.
1950 Dec 11: Mukti sena attacked Biratnagar and captured in Dec 23 and started provisional governemt in Dec 24 headed by KP Koirala.
1950 Dec 14: Mukti sena captured Jhapa.
1951 Jan 16: Nepali Congress agreed on ceasefire as requested by Nehru in Jan 10 but KI Singh continued.
1951 Feb 12: India mediated formal peace agreement between King, Rana & Nepali Congress known as "Delhi Accord".
1951 Feb 15: King Tribhuvan and major leaders of Nepali Congress returned from India after Delhi Agreement with Rana Regime. This day (Falgun 7, 2007) is/was marked as Democracy day in Nepal.
1951 Feb 21: Indian armed force intervened in support of the government. KI Singh and 100 rebels were captured.
1951 Apr 9: Bir Gorkha Dal led by Randhir Subba and Bharat Shamsher revolt against the new government.
1951 Apr 15 : government banned Veer Gorkha Dal.
1951 Apr 16: King Tribhuvan stripped PM Mohan Shamer from his position as supreme commander of Nepal Army.
1951 May 10-16: India mediated another negotiation between King, Rana and NC who agreed to established the 40 member advisory assembly.
1951 June 10: Rana PM Mohan shamsher formed another government with Nepali congress.
1951 Nov 6: Government fired on student protestors in Kathmandu.
1951 Nov 10: NC members resigned from the government.
1951 Nov 12: Rana PM Mohan Shamsher also resigned from the government.
1951 Nov 16: Matrika Prasad Koirala became the first commoner PM of Nepal after the end of Rana regime.
1951 Dec 14: Mohan Shumsher, Last Rana PM, went into self-imposed exile in India.
1952 Jan 22-24: Government troops suppressed a rebellion led by K. I. Singh in Kathmandu
1952 Jan 23: King Tribhuvan declared stated of emergency.
1952 Jan 25: Government banned Communist party of Nepal and Rastriya Mahasabha after Raksha Dal revolt.
1952 Feb 27: India sent 200 military personal in the name of assisting the government which stayed until 1970 Aug 18.
1952 May 26: BP Koirala became second president of the Nepali Congress Party.
1952 July 4: 40-member Advisory Assembly convened in Kathmandu.
1952 July 25: Accused of violating party principles and acting against the constitution, NC expelled PM Matrika P Koirala.
1952 Aug 6: PM MP Koirala resigned.
1952 Aug 10: King Tribhuvan took control of the government.
1952 Sep 4: King Tribhubana dissolved the Advisory Assembly.
1953 June: MP Koirala established National Democratic Party.
1953 Jun 15: Matrika Prasad Koirala became PM. (2nd term)
1953 Sep 2: Second Kathmandu Municipal election held. Wards were reduced from 21 to 18. Sadhana devi became first elected women representative from ward no 8. Candidates of the banned CPN won some 50 percent of the vote. Indian troops intervened in support of the government.
1954 Jan 30: First party congress of CPN held in Patan secretly while still being banned for 9 days. Manmohan Adhikari elected as the General Secretory. (link)
1954 May 28: 112-member Advisory Assembly convened in Kathmandu.
1955 Jan 10: NC launched a civil disobedience movement
1955 Jan 31: PM Koirala resined but The Royal Council of State refused to accept the resignation. King Tribhubana dissolved the Royal Council of State on February 18 and vested royal powers in Crown Prince Mahendra Bir Bikram.
1955 Mar 2: Prince Mahendra accepted the resignation of PM.
1955 Mar 13: King Tribhuvan died. Mahendra became new King of Nepal.
1955 Apr 14: King Mahendra took control of the government.
1955 Jul 10: King Mahendra dissolved Advisory Assembly.
1956 Jan 24-25: Sixth National Convention of Nepali congress held in Birgunj. Subarna Shumshere elected as the President.
1956: Political relation between China and Soviet Union started to break on the definition of Marxism-Leninism which affected CPN.
1956 Sep 28: 8th convention of CP of China. Manmohan Adhikari attended representing CPN. Keshar Jung Rayamajhi took acting-general secretary during his visit.
1956 Jan 27: Tanka Prasad Acharya as PM by the King.
1956 Apr: Ban lifted on Communist Party of Nepal.
1957 Feb 25-28: Chinese PM Zhou Enlai visited Nepal
1957 May 23: BP Koirala elected as the president of Nepali Congress.
1957 Jul 13: Tanka Prasad Acharya resigned as PM.
1957 Jul 27: Dr. KI Singh as PM by the King.
1957 Aug 9: NC, NNC, and PP formed the Democratic Front (DF).
1957 Sep 30: government announced the postponement of the national elections which were scheduled for October 8.
1957 May 28-Jun 7: Second National congress held of CPN. Soft-liner & pro-soviet Keshar Jung Rayamajhi elected as the General Secretary. Manmohan Adhikari could not attend as he was taking medical treatment in China. Mohan Bikram Singh elected as the central committee member.
1957 Nov 14: King Mahendra took direct control of the govt as KI Singh resigned as PM.
1957 Dec 7: Democratic Front (DF) launched a civil disobedience campaign in protest of the postponement of the national elections.
1958 Feb 1: King Mahendra formed a government composed of representatives of the DF and NC ended its civil disobedience campaign on Feb 4.
1958 May 15: Suberna Shamsher, Nepali Congress leader, appointed as PM by the King.
1959 Feb 12 (2015 Falgun 1 B.S.): King Mahendra promulgated the new constitution which had provisioned 109-member lower house and 36-member upper house.1959 Feb 18-Apr 3: First ever democratic election for parliament held in Nepal. Nepali Congress became the largest party winning over 2/3 seats (74 among total 109). (see elected members)
1959 Mar 30: The 14th Dalai Lama entered India from North east and established government of Tibet in exile in Apr 28 in Dharmasala, India (west of Nepal).
1959 May 4: Suberna Shamsher resigned as PM.
1959 May 27: BP Koirala became first elected Prime Minister of Nepal.
1960 Apr 27-30: King Mahendra visited USA & Canada. (link) Addressed US congress in Apr 28.
1960 May 7-13: Seventh National Convention of Nepali Congress held at Kathmandu. Bishweshwar Prasad Koirala as president.
1960 Sep 22: PM Koirala visited USA to attend UN general assembly.
1960: USSR President Marshal Voroshilov visited Nepal
1960: Chinese PM Zhou En-lai visited Nepal for second time.
1960 Dec 15 (B.S. 2017 Poush 1): King Mahendra dissolved the parliament, suspended the constitution, and imprisoned the PM BP Koirala and other leaders.