1876: Alexander Graham Bell invents the telephone, for which he receives two patents.
1885: American Telephone and Telegraph is formed with a charter to build and operate the original long-distance network.
1894: Alexander Graham Bell's second telephone patent expires, opening the telephone industry to competition.
Early 1900s: AT&T refuses to allow rival phone companies to connect to its network until they sell out to AT&T.
1913: AT&T settles its first federal antitrust suit in a deal that establishes the company as a government-sanctioned monopoly.
1925: AT&T establishes Bell Laboratories as its research and development subsidiary.
1927: AT&T begins trans-Atlantic telephone service between the United States and London. The initial capacity is one call at a time, at a cost of $75 for the first three minutes.
1937: Clinton Davisson of Bell Telephone Labs wins the Nobel Prize in physics, becoming the first of seven Nobel Prize winners produced by AT&T.
1946: AT&T begins offering mobile telephone service. Initially, no more than 12 to 20 simultaneous calls could be made in an entire metropolitan area.
1974: MCI and, later, the U.S. Justice Department sue AT&T on antitrust grounds.
1982: Justice Department and AT&T sign landmark agreement breaking up the AT&T monopoly by allowing long-distance competition and creating seven independent regional phone companies.
1984: Bell System breakup takes effect. AT&T retains Bell Laboratories research arm, Western Electric phone manufacturing arm and long-distance business.
1991: AT&T acquires computer maker National Cash Register, or NCR, in an attempt to integrate computing and telecommunications.
1993: AT&T reaches a merger agreement with McCaw Cellular Communications, the largest provider of cellular service in the United States.
1995: AT&T announces it is restructuring into three separate companies: a services company retaining the AT&T name; a products and systems company (later named Lucent Technologies); and a computer company (which reassumed the NCR name).
1997: AT&T opens talks with SBC Communications about a possible merger valued at $50 billion or more. The talks break down a month later after federal regulators voice antitrust concerns.
1999: AT&T acquires TCI, the second-largest cable company in the United States. TCI becomes AT&T Broadband. The following year, AT&T Broadband acquires cable company MediaOne and becomes the largest cable company in the United States.
2000: AT&T announces it will reorganize into a family of companies: AT&T (including AT&T Business and AT&T Consumer), AT&T Wireless and AT&T Broadband.
2001: AT&T Wireless is spun off.
2002: AT&T Broadband completes a merger with Comcast.
2003: Reported talks between AT&T and BellSouth about a possible merger end without a deal.
2004: AT&T's stock (ticker symbol: T) is dropped from the Dow Jones industrial average. Company stops selling traditional consumer phone service.
Jan. 30, 2005: AT&T agrees to be acquired by SBC for $15 billion.