“We are very disappointed with the verdict because what we have done is only exercising our constitutional rights,” Lee said outside the courtroom, Bloomberg reports. “But it’s a badge of honor for us that we are convicted for walking together with the people of Hong Kong for democracy and freedom.”

Martin Lee Chu-ming who was convicted for an unauthorized proted in 2019, declined to comment on the verdict.

Diplomats from the European Union, Germany, Sweden, Canada, Australia and New Zealand attended the hearing.

The court case is the latest in a series of major setbacks in recent weeks for Hong Kong’s pro-democracy camp. The group on trial comprised veteran activists who have for years supported causes such as human rights and women’s rights, and organized vigils commemorating the 1989 crackdown on student demonstrators in Tiananmen Square.

The decision comes shortly after top Chinese lawmakers approved a sweeping plan that effectively ends open elections in Hong Kong. The city’s government separately charged some 47 prominent opposition figures with “conspiracy to commit subversion” under a national security law imposed last year that carries sentences as long as life in prison.

Martin Lee was among 15 prominent democracy activists accused last year of participating in a historic – but unauthorized – march on August 18, 2019. The mostly peaceful demonstration was one of the biggest held during months of unrest over proposed extradition legislation, with an estimated 1.7 million people attending.

The case is part of a push to disband Hong Kong’s democratic institutions and clamp down on the opposition’s moderate wing, according to Michael Davis, a professor of law and international affairs at O.P. Jindal Global University in India and a former law professor at the University of Hong Kong.

“The government has chosen 15 people very carefully out of the 1.7 million protesters, and all are moderate democratic activists and politicians,” Davis said. “It’s very hard to separate this trial from the current effort to prevent participation in the political process.”

Hong Kong police have swept up many of the city’s established opposition leaders among the more than 10,000 activists arrested since the protests erupted in June 2019. Some, such as Jimmy Lai, face multiple prosecutions, including charges under the national security law.

Two former opposition lawmakers, Au Nok-hin and Leung Yiu-chung, had previously pleaded guilty to charges related to the August 2019 protest. Six other people are expected to go on trial over the demonstration later this year.

Martin Lee, a London-trained lawyer, has stoked Beijing’s ire for more than three decades, dating back to his support for the Tiananmen Square protests and subsequent defeat of the pro-establishment camp in Hong Kong’s first direct legislative elections. He sat on the committee that drafted Hong Kong’s post-handover charter, founded the Democratic Party and served as a lawmaker until his retirement in 2008.

Chinese authorities have accused him of being a “traitor” for testifying before the U.S. Congress, and in August 2019 labeled him as part of a “New Gang of Four” in a publication under the Communist Party’s top legal body. The piece also named Lai and Ho, a former Democratic Party leader and chief executive candidate, as members of the “gang” – a reference to a Communist Party faction jailed for attempting to seize power after Mao Zedong’s death in 1976.

Nonetheless, Martin Lee had avoided arrest until last year. In an op-ed published in the Washington Post last year, he described his arrest as “part of a large plan” to snuff out dissent in Hong Kong.

“But once Hong Kong’s human rights and rule of law are rolled back, the fatal virus of authoritarian rule will be here to stay,” he said.