The Portland Symphony Orchestra (PSO) was established in 1924 in Portland, Maine, United States, as the Amateur Strand Symphony Orchestra. Started by a small group of musicians who had sent out invitations to join their organization to people in the area, they had their first rehearsal the following year with 75 instrumentalists, giving their first concert a month later at the Strand Theater. In 1927, the orchestra changed its name to the Portland Municipal Orchestra, and again in 1932 to the Portland Maine Symphony. In 1969, the orchestra's name was changed to the Portland Symphony Orchestra, after that name became available when an older orchestra in Portland, Oregon, relinquished it in favor of a new name, the Oregon Symphony. Today, the Portland Symphony Orchestra is recognized to be one of the top orchestras of its size in the country. The concert season runs from September to May and during July, and performs a variety of concerts in their home concert hall, Portland's Merrill Auditorium.