In 1888 the club merged with Ipswich Rugby Club to form Ipswich Town F.C. In 1890, the club entered the qualifying rounds of the FA Cup for the first time and was knocked out in the final qualifying round by the 93rd Highlanders. The club experienced scant success in the Cup during the 1890s but won a number of local cup competitions, including the Suffolk Senior Cup and the Ipswich Charity Cup. Having received invitations to join from both the Southern League and the Norfolk & Suffolk League, Ipswich joined the latter in the 1899–1900 season, finishing fourth in their first league season. They were league runners-up in 1902–03. In 1903 they also entered a team into the new South East Anglian League and were its inaugural champions. They left the South East Anglian League in 1906, but continued playing in the Norfolk & Suffolk League. In 1907, Ipswich became founder members of the Southern Amateur League. The club narrowly avoided relegation in many of the following seasons, and suffered a club record 15–1 defeat at the hands of the Corinthians at Portman Road on New Year's Day, 1910. The outbreak of the First World War and the commandeering of Portman Road by the Army curtailed the 1914–15 season and organised football did not return until the 1920–21 season. Just one year later, Ipswich Town became champions of the Southern Amateur League, clinching the title on the last day of the season. The club won the league a further three times, in 1929–30, 1932–33 and 1933–34, before becoming founder members of the Eastern Counties Football League at the end of the 1934–35 season. In 1936, local businessman Leonard P. Thompson threatened to lead a breakaway from the amateur club to create an entirely separate professional club, Ipswich United. John Murray Cobbold, the club President, called together rival factions for a meeting at the Town Hall on 1 May 1936, at which it was agreed that Ipswich Town should turn professional. The club was unanimously elected to the Southern League for the 1936–37 season and former Irish international footballer Mick O'Brien was appointed as the club's first professional manager. The club's first professional game at Portman Road resulted in a 4–1 win against Tunbridge Wells Rangers and the club went on to win the Southern League in their debut season. O'Brien left after just one season following the death of his wife. Ipswich Town were managerless until 10 November 1936 when the club appointed Scott Duncan, who had left recently relegated Manchester United.