US Congressman, US Senator. A member of the Democratic Party, he served in the US House of Representatives from Massachusetts's 5th district from January 1975 until January 1979 and in the US Senate from January 1979 until January 1985. Born a twin to a working-class family of Greek ancestry, he graduated with a Bachelor of Arts Degree in Economics from Dartmouth College at Hanover, New Hampshire in 1962. Afterwards, he served in as the Peace Corps volunteer in Ethiopia from 1962 to 1964 and as the West Indies Peace Corps Country Director from 1967 until 1968. He went on to further his education, receiving a Master of Public Policy Degree from the Kennedy School of Government at Harvard University in Cambridge, Massachusetts and Doctor of Law Degree from Yale Law School in New Haven, Connecticut. After settling in Lowell, Massachusetts, he entered politics in 1969 when he served two terms on the Lowell City Council and later as the Middlesex County Commissioner. In 1974 he ran for Congress on the Democratic ticket, easily defeating his Republican opponent by a wide margin. He was re-elected in 1976 and two years later he ran for US Senate and defeated the incumbent Republican, Edward Brooke. During his tenure in both the House and Senate, he played an important role in helping to support historical preservation and environmental conservation. In 1983 he was diagnosed with non-Hodgkin's lymphoma and the following year he retired from the US Senate at the end of his term and was succeeded by John Kerry. After his disease went into remission, he returned to politics, running for the 1992 Democratic Party's nomination for President. Although he achieved some early success, he eventually pulled out of the race following Bill Clinton's success in the Super Tuesday primaries. Two years later he unsuccessfully led an attempt to establish a third political party. In 1996 his lymphoma returned and he died of complications from the disease the following year at the age of 55. In January 1998 the Tsongas Arena in Lowell, Massachusetts was dedicated in his honor.