Story highlights Suu Kyi and 33 other members of her party were elected to the lower house 
 
 They had delayed their parliamentary debuts over the wording of the oath of office 
 
 The oath of office is a historic moment in Myanmar's recent reforms 
 
 A previous election success by Suu Kyi's party in 1990 was ignored by the military rulers 
 
 Myanmar opposition leader Aung San Suu Kyi was sworn in Wednesday as a lawmaker for the first time, a key step in the country's recent shift toward democracy after decades of repressive military rule. 
 
 Suu Kyi, a pro-democracy campaigner who spent years under house arrest, traveled to the parliament in the capital, Naypyidaw, to take up the seat she won in elections last month. 
 
 It was a historic moment for the Nobel laureate, who has spent decades campaigning for, and being deprived of, human rights in Myanmar. 
 
 Suu Kyi led her party to a landslide victory the previous time Myanmar held multiparty elections, in 1990. But the military junta ignored the results and kept her under house arrest. 
 
 She and 33 other newly elected members of her party, the National League for Democracy, took an oath of office for the lower house of parliament that they had initially refused to accept because of its wording, which called for protection of the country's constitution. 
 
 The NLD considers the constitution undemocratic and has said it wants to change it. 
 
 JUST WATCHED Myanmar looks for economic revival Replay More Videos ... MUST WATCH Myanmar looks for economic revival 02:02 
 
 JUST WATCHED British PM's historic visit to Myanmar Replay More Videos ... MUST WATCH British PM's historic visit to Myanmar 02:40 
 
 JUST WATCHED Rushing to do business in Myanmar Replay More Videos ... MUST WATCH Rushing to do business in Myanmar 02:17 
 
 The party had asked the Myanmar authorities to adjust the wording of the oath to say that lawmakers would "abide by" the constitution rather than "protect" it. 
 
 Suu Kyi and the other recently elected NLD members delayed their debuts in parliament over the issue, but the government of President Thein Sein, a former military official, made no sign of moving to accommodate the request. 
 
 On Monday, Suu Kyi and the NLD backed down from the demand to have the wording changed, ending the impasse. 
 
 Suu Kyi said she would take the oath "for the country and for the people." She added that her decision had been encouraged by voters, parliament members and representatives of Myanmar's ethnic minority groups. 
 
 During a visit to Myanmar this week, U.N. Secretary-General Ban Ki-moon expressed support for Suu Kyi's climbdown over the oath. "Real leaders demonstrate flexibility for the greater cause," he said after meeting with her at her lakeside residence in Yangon. 
 
 U.S. Secretary of State Hillary Clinton congratulated Suu Kyi and her party on the occasion of their swearing-in. 
 
 "This is an important moment for Burma's future. A genuine transition toward multi-party democracy leading to general elections in 2015 will help build a more prosperous society," Clinton said in a statement, using the other name for Myanmar. "I encourage all political parties, civil society representatives and ethnic minority leaders to work together to address challenges and seize new opportunities for a more democratic, free, peaceful, and prosperous future." 
 
 Myanmar's authoritarian military rulers are loosening their grip on power after decades of stifling dissent and limiting freedoms. 
 
 Thein Sein's civilian government was sworn in just over a year ago. 
 
 In the past 12 months, the government has pardoned hundreds of political prisoners, secured a cease-fire with Karen rebels and agreed to negotiate with other ethnic rebel groups. 
 
 The success of Suu Kyi and her party at the by-elections last month -- the NLD won 43 seats, 34 of them in the lower house -- was welcomed by the United States and European Union as a sign of progress toward democracy. 
 
 Her presence in parliament Wednesday illustrates the pace at which Myanmar is changing: She was released from house arrest less than a year and a half ago. 
 
 Next month, she will make her first trip overseas in more than two decades. She plans to visit Norway to make a belated acceptance speech for the Nobel Peace Prize she was prevented from collecting in 1991 because she was in detention. 
 
 She took her seat in the chamber Wednesday alongside incumbent legislators, many of whom are former military officials. 
 
 Myanmar's legislature has 664 seats, more than 80% of which are still held by lawmakers aligned with the military-backed ruling group, the Union Solidarity and Development Party. 
 
 Control of parliament will not change, but the entry of the NLD members nonetheless gives the party a notable presence. 
 
 Many Western governments have taken steps to ease sanctions on Myanmar, also known as Burma, in response to its political reforms. But international officials have also cautioned that the country still has a long way to go. 
 
 Speaking last week ahead of his trip, the United Nations' Ban said that Myanmar's "fresh start is still fragile." 

 NAYPYITAW, Myanmar Myanmar opposition leader Aung San Suu Kyi took a historic oath on Wednesday to join a parliamentary system crafted by the generals who locked her away for much of her long struggle against dictatorship, ushering in a dramatic new political era. 
 
 The 1991 Nobel Peace Prize winner's debut in a parliament stacked with uniformed soldiers could accelerate reforms that have already included the most sweeping changes in the former British colony since a military coup 50 years ago. The signs of change have already prompted some countries to suspend sanctions. 
 
 But the wildly popular daughter of assassinated independence hero Aung San also faces the difficulty of managing the expectations of a nation impatient for change and the hopes of Burmese who see her as a sole beacon for democratic freedom. 
 
 It is unclear how rapidly she can deliver on her ambitious campaign promises, including the overhaul of Myanmar's army-drafted constitution, in a legislature dominated by former members of the military junta who ruled for nearly half a century before ceding to a quasi-civilian government last year. 
 
 "Only time will tell," she replied when asked by a Reuters reporter of the day's significance, as she waded through a chaotic throng of reporters on her way to the chamber where she took the oath in a shortened 40-minute session. 
 
 Later, she told reporters: "I have always been cautiously optimistic about developments. In politics, you also have to be cautiously optimistic." 
 
 Suu Kyi's entry into parliament comes a month after her party's landslide victory in a by-election and two days after backing down in a standoff over the wording of an oath to protect the constitution sworn by all new members of parliament. 
 
 The parliamentary session was to have ended on Monday but was extended in part to allow Suu Kyi and fellow members of the National League for Democracy (NLD) to take their seats. 
 
 Entering the chamber, she at first sat down on her own, near the block reserved for serving military men who have a quarter of the seats under the constitution, and seemed relaxed as other lawmakers greeted her. 
 
 She then lined up with colleagues to take the oath, including a pledge to uphold a constitution her party wants to change because it gives the military a leading political role. 
 
 Taking a conciliatory tone, Suu Kyi said she remained open on the question of revising the oath. "The key to all of this is flexibility and practicality," she said. 
 
 "GOODWILL TOWARDS THE MILITARY" 
 
 Asked if she felt awkward working with the military, she replied, "Not at all, I have tremendous goodwill towards the military. It doesn't in any way bother me to sit with them." 
 
 Her comments reflect the dramatic scale of change in the former Burma, given the military's past treatment of Suu Kyi, who was first detained by the army in 1989, and then spent 15 of the next 21 years in detention until her release from house arrest in November 2010. 
 
 Many lawmakers hope Suu Kyi's parliamentary debut will be a catalyst for further reform by the government of President Thein Sein, a former general who has freed hundreds of political prisoners, loosened strict media controls, legalized trade unions and protests, and started a dialogue with ethnic minority rebels. 
 
 "Parliament will be stronger because of her good relationship with the international community," said Khin Maung Yi, a lawmaker from the National Democratic Force party. "We parliamentarians have wanted her in the legislature for a long time ... Many laws have to be changed and amended." 
 
 Suu Kyi's story of triumph over tragedy began in 1988 when she left her family life in Britain to take care of her dying mother in Yangon. She soon found herself thrust into politics as nationwide protests erupted against the military, addressing crowds of thousands before her 1989 arrest. 
 
 A year later, her NLD won 392 of 485 house seats in a rare election, which the regime ignored. 
 
 She was awarded the Nobel Peace Prize in 1991 during the first of three stints under house arrest. Even in her brief periods of freedom, she never left Myanmar, afraid the military would not let her return. 
 
 She refused to leave to be with British husband Michael Aris, an Oxford University academic, when he was diagnosed with prostate cancer. He died in Britain in 1999. 
 
 Four years later she survived an assassination attempt in an attack on her motorcade in which dozens of supporters were killed. This led to another spell in detention ordered by a regime that brutally suppressed dissidents. 
 
 But as Myanmar changes, so does Suu Kyi. While her decades of defiance were lauded by the world, her decision to join an imperfect political system has also been saluted by the West, which has started relaxing sanctions. 
 
 And her campaign promise to amend the constitution could put her on a collision course with the army. Last week the military filled its 25 percent house quota with higher-ranking officers in an apparent attempt to boost its parliamentary clout. 
 
 But even some of Suu Kyi's fierce rivals in the ruling Union Solidarity and Development Party (USDP) see her presence as a boon for a parliament with limited powers. 
 
 "With Suu Kyi on board, parties will be more diverse, with different perspective and opinions," said Kyaw Soe Lay, a lower house USDP lawmaker. "This works in the interest of those in the parliament." 
 
 (Additional reporting by Thu Rein Hlaing; Editing by Alan Raybould, Jason Szep and Jeremy Laurence)
– In what pro-democracy groups hope is the dawning of a new era in Burma, Aung San Suu Kyi took the oath of office and took her place in the country's parliament for the first time today. Suu Kyi, whose National League for Democracy swept by-elections in April, joined dozens of other lawmakers from her party in taking the oath, CNN reports. The NLD members backed down from a demand to change the swearing-in oath to remove a promise to protect a constitution they consider undemocratic. "We've always believed in being flexible throughout the years of our struggle because that is the only way in which we can achieve our goal without violence," Suu Kyi, who spent most of the last 20 years under house arrest, said after agreeing to stick to the original wording. "I don't think flexibility will be a new concept for us." As she entered the parliament building today, a Reuters reporter asked her if she considered this to be a historic day for Burma. "I think only time will tell," she replied.