Baltimore Technologies, for some time one of the most visible stars in the Irish technology firmament, is also one of its most extraordinary corporate tales.

Never, ever, boring, the impudent technology security company came from nowhere and marched into one of the most formidable tech sectors, for a time threatening to dominate or even buy up its elder US rivals.

The company's journey from A to B has been constantly surprising. In its five years under Fran Rooney's guidance, Baltimore Technologies achieved a level of outward success and international focus unequalled by any other Irish technology company. At one point after it floated on the Nasdaq, its market capitalisation at £7.5 billion sterling (€12.34 billion) surpassed even that of the Bank of Ireland. Before trading began yesterday its market cap was £132 million. .

Mr Rooney became one of the only names in the Irish technology industry to enjoy a high level of recognition, even with the general public. Now, the company that is virtually synonymous with Mr Rooney has lost him as its chief executive and is threatened with a buyout or even possible closure.

But the company has a much longer history than its relatively brief association with Mr Rooney. Baltimore existed, albeit pretty quietly, for nearly 20 years before Mr Rooney snapped it up for £300,000 in 1996. The Dublin company was actually established in the mid1970s by Trinity College lecturer Dr Michael Purser, and went through several incarnations. For a time, it focused on communications software. By the time Mr Rooney was looking for a company to buy, it operated as a low-profile, six-person consultancy firm in the area of network security.

Enter Mr Rooney. Set against other technology company leaders who had begun to emerge around the same time, he was an unlikely entrepreneur. In among the campus companies with computer scientist academics came a Ringsend-born Dubliner who grew up in Cabra and went to work immediately after leaving school in 1974.

Rather than the university degree in mathematics or engineering and the lecturer's post, Mr Rooney's business and computing knowledge came from a combination of night classes and self-driven research.

After finishing school, the young Dubliner went to work as a civil servant in the finance division of the Department of Posts and Telegraphs. During 16 years in the civil service, he studied at night to acquire a number of qualifications: a diploma in public administration, a degree in administrative science, and a qualification as a chartered accountant. He also followed several computing courses, enough to enable him to leave the service and work with computers.

Ironically, upon leaving the civil service he ended up working in his old Government department in a private capacity, as a systems analyst and programmer. Then he moved to a career in finance, for a time running NIB's credit card division. By this point, he had an itch to set up on his own, and, spotting a gap in the market, created Meridian, a company that recovered VAT for multinational companies operating in Europe. While at Meridian, he met businessman Mr Dermot Desmond, who chose Mr Rooney to successfully expand his software venture, Quay Financial Software. Quay's eventual sale netted £15 million for Mr Desmond and proved Mr Rooney's management abilities.

Mr Rooney then began to seek a company within the security software area, in which he had developed a strong interest because, as the Internet began to take off and organisations connected their in-house computer networks to the Wild West of the Net's unpoliced networks, he believed it was a sector offering future growth. He had also recognised that, given the time and expertise needed to build software in this complicated area, it was easier to buy and develop a company already in the sector rather than start one from scratch.

Tiny Baltimore, with its small £50,000 revenue stream in 1996, seemed a good choice but Mr Rooney couldn't swing the finances to purchase the company outright. He turned to Mr Desmond, who agreed to bring in some associates to back the company. But he required Mr Rooney to also commit the bulk of his own earnings from Quay as a mark of personal dedication to the company, which he did.

From then on, Mr Rooney's success depended entirely on Baltimore's success. Yet it is doubtful that in his wildest ambitions he could have had any inkling of how spectacular the company's growth would be.

Certainly nobody would have predicted in 1996 that an Irish security company would become a global player. A Siemens spin-off in Dublin, SSI, was having great success with messaging security software at the time, but Baltimore was a different proposition altogether. Mr Rooney decided to anchor the company around the then-nascent area of public key infrastructure (PKI), a complex system for creating a secure computing and communications environment that would need global commitment to work. It was one of many possible approaches to looming security problems that were emerging from the increased use of electronic communications and storage systems (see side panel).

In addition, the security software area was dominated by very large American competitors in an industry where longevity, reputation and trust were considered by analysts to be absolutely central to success. However, the company, a model of successful self-promotion, worked hard to establish a European profile, and then began to create a US name identity.

In 1997, when the company was little more than an unknown blip in the security technologies world, Baltimore swaggered into the leading annual industry event, the RSA Data Security Conference in San Francisco, and handed out Baltimore-logoed cigars. The next year they were back, throwing a memorable party with alcohol purchased cheaply in Dublin Duty Free, still trying to look bigger than they were by staffing their stand with the entire Dublin office. Again, they were hugely overshadowed by US competitors like RSA, CertCo, Entrust and VeriSign - companies that had been in the security technologies sector for years and had well-established brand identity.

By 1999, a significant player in the European security market and, at 280 people, much bigger after merging with British security company Zergo, Baltimore brashly decided to co-sponsor the RSA. There they were, the Baltimore name and logo printed on all the conference materials, pitching themselves again as if they were much, much better known, getting attention by hosting yet another punchy party in, of all places, a San Jose billiards hall. Last year and this year, Baltimore had one of the larger RSA stands, were snapping at the heels of their biggest rivals, and were widely considered to throw the best parties.

For the best part of five years, the company was an analyst's darling, often surpassing analysts' estimates (although always still operating at a loss).

Big contract wins kept pushing up the profile of the company and its 1999 reverse takeover of British competitor Zergo set Baltimore up for an eventual Nasdaq listing.

Many within the company consider last year's second annual Baltimore conference in Orlando to have been the corporate peak - Baltimore was on top of its game, a leader in global PKI with a strong market cap.

That's also when the entire economic climate shifted brutally. The spring 2000 market plummet was beginning to wallop all technology sectors, not just the wobbly dotcoms. Baltimore remained upbeat as analysts predicted security would remain a massive growth area despite the downturn. But they were wrong.

Baltimore's share price was sliding by late last year and, in retrospect, Mr Rooney seemed to lose nerve. Analysts and, by all accounts, internal Baltimore management were arguing for cutbacks and restructuring as many tech companies began to hit the wall, but Mr Rooney seemed reluctant to make changes. Several senior industry leaders say the perception outside Baltimore was that the company had become a oneman show, with little consultation among the management team and Mr Rooney taking most decisions.

In addition, Mr Rooney's relationship with his board had reportedly remained adversarial after the merger with Zergo. Also, communication problems seemed to haunt Mr Rooney - statements to press and analysts caused instability with the share price and the markets gradually lost confidence in the company. Baltimore's shares went to rockbottom and it was rumoured that both the board and many investors wanted Mr Rooney removed from the helm.

This week's announcement that Mr Rooney would step down was thus sudden and perhaps earlier than anticipated, but not unexpected. The consensus among analysts and peers seems to be that the Dubliner's strengths lay in providing the vision, energy and creativity needed to accelerate a company into high growth. But different skills were required once the economy slumped and brutal cost-cutting measures were needed.

As one industry peer and entrepreneur notes: "The pressure he was under to deliver [high] growth must have been phenomenal." It's the kind of pressure few can tolerate without experience, he says, and many buckle under it. Many believe Mr Rooney now has that experience if he wants to try again with a new company. As one current critic says: "I'd invest in Fran now in his next venture."