Microsoft History: From Altair BASIC and MS-DOS to Copilot, Agent 365 and Microsoft 365 E7

The through-line: license software, not machines​

Microsoft's own timeline says Bill Gates and Paul Allen started the company in 1975. Microsoft's "About" page says the pair were inspired by the January cover of Popular Electronics and set out to write software for the Altair 8800. The company name was sometimes written "Micro-Soft", a blend of microprocessors and software.

Many popular retellings give April 4, 1975 as the birthday, and Microsoft marked its 50th anniversary on April 4, 2025. Microsoft's own milestone list only says "1975" for the founding. Treat the April date as the company's anniversary convention. The primary chronologies don't pin it down further.

The pattern that follows is simple. Microsoft wrote software that other companies' hardware could run, and it kept finding the next layer to own.

1979–1989: Bellevue, MS-DOS and the first Windows​

• Relocation: Microsoft's chronology says it moved from Albuquerque to Bellevue, Washington on January 1, 1979, and incorporated on June 25, 1981.
• IBM PC: IBM introduced its personal computer on August 12, 1981, with Microsoft's 16-bit operating system, MS-DOS 1.0. Microsoft's own milestone page describes this as its entry into the operating systems business. It says IBM's PC, MS-DOS 1.0, plus BASIC, COBOL, Pascal and other Microsoft products became the new industry standard.
• Why it mattered (analysis): The widely told account is that Microsoft kept the right to license MS-DOS to other manufacturers, which let it ride the wave of IBM-compatible clones. The primary pages above confirm the launch, not the contract terms, so treat the licensing detail as the commonly reported explanation rather than something verified here.
• Windows arrives: On November 20, 1985, Microsoft released Windows 1.0 as a graphical user interface for MS-DOS, two years after Bill Gates first announced it in 1983. That makes Windows 1.0 a layer on top of DOS, not a replacement for it.
• Redmond and the IPO: Microsoft moved to its Redmond campus on February 26, 1986, and went public on March 13, 1986, at a $21 offering price that rose to $35.50 by the end of the day.

1989–1999: Office, Windows 3.0, Windows 95 and enterprise​

A correction on Office. A common version says Office was first bundled for Windows in 1990. Microsoft's own pages put the earliest Office suite in 1989. Its milestone entry for June 19, 1989 calls it the first version of Office, released for the Macintosh. The facts page separately lists August 1, 1989 as the date it introduced the earliest version of the suite. Microsoft's two pages differ on the exact day, so the safe summary is "mid-to-late 1989, on the Mac first".

Key dates from the corporate chronology:

Windows 95 was marked by midnight store launches and customers lining up worldwide. Gates's "Internet Tidal Wave" memo of May 26, 1995 steered Microsoft toward integrating Internet services into its products. That helps explain the browser fights of the late 1990s.

Antitrust. The US government's antitrust case, filed in the late 1990s over how Microsoft treated competing browsers, was a defining legal challenge. The sources gathered here do not detail the case's procedural history, so this piece doesn't cite specific filing or ruling details.

2000–2010: XP, Xbox and the cloud bet​

Steve Ballmer became president and CEO on January 13, 2000. Windows XP launched on October 25, 2001, and Xbox followed on November 15, 2001. Microsoft's milestone page also ties Xbox to later cloud infrastructure, saying it fed the demand for live gaming that led to what became Azure.

On the business side, the acquisition history shows Great Plains Software (2000) and Navision (2002) joining the company. Those deals seeded what later became its business applications line.

The cloud turn is well documented:

• Windows Azure launched on October 27, 2008, as an internet version of Windows running from Microsoft's own data centers. It became generally available in 2010 and was later renamed Microsoft Azure.
• Microsoft's 2009 annual report describes October technical previews of Windows Azure and the Azure Services Platform, which it called key to its software-plus-services strategy. It listed Azure among the products to roll out in fiscal 2010.
• That same report also notes Microsoft's first-ever annual revenue drop, from $60.4 billion to $58.4 billion, during the 2009 recession. It is a reminder that the cloud push began while PC sales were soft.

2014–2019: Nadella, cross-platform and developers​

Satya Nadella was named CEO on February 4, 2014, succeeding Steve Ballmer as only the third leader in the company's history. The visible changes came quickly:

• Office for iPad launched on March 27, 2014.
• On October 20, 2014, Nadella announced Azure additions including the Cloudera Hadoop package and the CoreOS Linux distribution. Microsoft's own page frames this as a notable shift toward Linux and open source.
• A new mission statement in June 2015 moved Microsoft's goal from making the PC ubiquitous to empowering every person and organization.

Deal figures, checked against Microsoft's pages:

• LinkedIn: a $26.2 billion acquisition announced June 13, 2016 and completed December 8, 2016. Microsoft's facts page lists the completion on that later date.
• GitHub: acquired for $7.5 billion in stock, with the announcement dated June 4, 2018. The facts page records the completed deal on October 26, 2018.
• Dynamics 365 was introduced on July 6, 2016, and Microsoft Teams rolled out to Office 365 customers worldwide on March 14, 2017.

The AI turn: OpenAI and Copilot​

On July 22, 2019, Microsoft and OpenAI announced a multiyear partnership with a $1 billion Microsoft investment. The terms were specific. They would jointly build Azure AI supercomputing technologies, OpenAI would port its services to Azure, and Microsoft would become OpenAI's preferred partner for commercializing new AI technologies. That is narrower than a claim that the deal gave Microsoft control of AI development. It was an infrastructure and commercialization arrangement.

Then the Copilot era:

• GitHub Copilot became generally available on June 21, 2022.
• AI-powered Bing and Edge were introduced on February 7, 2023. Microsoft 365 Copilot was introduced on March 16, 2023.
• The Copilot brand was unified across Bing, Edge, Microsoft 365 and Windows on September 21, 2023.
• Microsoft 365 Copilot reached general availability for enterprise customers on November 1, 2023, at $30 per user per month. That GA was for enterprise customers, not every Microsoft 365 subscriber.
• Copilot+ PCs were introduced on May 20, 2024.

2026: Agent 365 and Microsoft 365 E7​

This is the newest chapter, and the details matter for IT admins and licensing teams.

• Microsoft announced Agent 365 and Microsoft 365 E7 on March 9, 2026, with general availability set for May 1. Microsoft describes Agent 365 as a control plane that gives IT and security leaders one place to observe, govern, manage and secure agents.
• Microsoft 365 E7 unifies Microsoft 365 E5, Microsoft 365 Copilot and Agent 365. It also includes Microsoft Entra Suite and advanced Defender, Intune and Purview security capabilities.
• Microsoft's announcement lists E7 at $99 per user per month and Agent 365 at $15 per user per month. E7 is available with and without Teams.
• Independent analyst firm Directions on Microsoft confirms that Agent 365 became generally available alongside E7 on May 1, 2026. Microsoft's Partner Center announcements also record the May 1 general availability.
• Directions on Microsoft calls Agent 365 the only entirely new component of the suite. It expects Agent 365 to keep gaining features that weren't complete at launch.

A word of caution. Microsoft's figures for agent adoption come from Microsoft. A GA announcement shows a product exists and has a price. It does not show that enterprises have deployed agents at scale or that the governance works as advertised. Independent write-ups also differ on some component prices. For example, one licensing guide lists Entra Suite at $12 per user per month. Directions on Microsoft lists it at $9, and Microsoft's announcement gives only the $99 bundle price. Check current price lists with your reseller before budgeting.

What the history tells us​

• Platform first, then layers. DOS and Windows made Microsoft the default software layer on PCs. Office, SQL Server and later Azure, Teams and GitHub added layers on top.
• Pivots followed pressure. The Internet memo, the 2009 revenue dip and the pivot to cross-platform Office each came as the PC-centric model hit limits. This is analysis, not a claim any single source makes.
• Identity and security are now the product. E7 bundles Entra, Defender, Intune and Purview with Copilot. That shows the company treating governance as part of the AI offering.

Fifty years on, the company that sold a BASIC interpreter now sells a control plane for software agents. Whether that last pivot pays off is the open question, and only deployment data will answer it.

Correction (October 21, 2026): three dates in this article were corrected. The LinkedIn acquisition was announced on June 13, 2016 and completed on December 8, 2016 (the earlier text called December 8 the announcement date). Microsoft Teams reached general availability on March 14, 2017, not March 17. And Windows 1.0 was released on November 20, 1985, two years after Bill Gates first announced Windows in 1983; the text now says "released" rather than "announced."