May 17 (Reuters) - French media group Vivendi has invested over 5 billion euros ($5.9 billion) in Italy over the past three years as part of tycoon Vincent Bollore's stated ambition to build a southern European media powerhouse.
** MAY-JUNE 2015: Vivendi receives an 8.3 percent stake in TIM as part-payment for selling Brazilian broadband group GVT to Spanish carrier Telefonica TEF.MC. After buying additional shares on the market, Vivendi becomes TIM's top shareholder with a 14.9 percent stake.
** JULY 2015 - MARCH 2016: Vivendi raises its TIM stake to 24.9 percent, just below the 25 percent threshold that would force it to launch a mandatory takeover bid. It later trims its stake to around 24 percent.
** MARCH 2016: TIM Chief Executive Marco Patuano resigns as Vivendi tightens its grip on the group and is succeeded by Flavio Cattaneo.
** APRIL 2016: Vivendi agrees to buy Mediaset's pay-TV unit Premium. The deal would give Vivendi full control of Premium and hand the two companies a 3.5 percent stake in each other. It also secures Italian tycoon and former prime minister Silvio Berlusconi, Mediaset's largest shareholder, as an important ally for Bollore.
** JULY 2016: Vivendi backs away from the deal, calling Premium's business plan unrealistic.
** AUGUST-DECEMBER 2016: After a lengthy war of words, Mediaset sues Vivendi for damages and asks Milan judges to enforce the pay-TV contract signed in April.
** DECEMBER 2016: Vivendi accumulated just under 30 percent of Mediaset in a hostile raid that draws the ire of Rome. The holding makes Vivendi the second-biggest investor in Mediaset after Berlusconi's Fininvest holding.
Italy's communications authority AGCOM and market regulator Consob start looking into Vivendi's stake building.
** FEBRUARY 2017: Italian prosecutors launch a probe into Bollore and Vivendi's CEO Arnaud de Puyfontaine for alleged market manipulation in the Mediaset stake building.
** MARCH 2017: Vivendi and Mediaset sue each other for defamation, seeking damages, as a trial kicks off in Milan.
** APRIL 2017: Italy's communications regulator AGCOM gives Vivendi a year to cut its stake in either TIM or Mediaset to comply with antitrust regulations that prevent excessive concentration of power in both the telecoms media sectors.
** MAY-JUNE 2017: Vivendi tightens its grip on TIM by appointing two thirds of the phone group's board and making de Puyfontaine TIM's executive chairman.
Separately, Vivendi appeals AGCOM's request to reduce its stake in either TIM or Mediaset, with a first hearing by a regional administrative court scheduled for July 4, 2018.
** JULY 2017: TIM CEO Flavio Cattaneo leaves TIM after 16 months in the job following clashes with Vivendi.
** SEPTEMBER 2017: Italian market regulator Consob rules that Vivendi has de facto control of TIM. Rome threatens to fine TIM over its failure to notify the government that Vivendi had assumed control of the phone group.
TIM appoints Amos Genish, a favorite of Bollore, as its new chief executive.
** OCTOBER 2017: Police raid Vivendi's Paris headquarters as part of a probe into its stake building at Mediaset.
Italy's government moves to rein in Vivendi's influence by activating so-called golden powers over TIM, giving it a say in all strategic decisions.
TIM's board approves the creation of a joint venture with Vivendi's pay-TV unit Canal+. The decision is later challenged by some independent directors.
** FEBRUARY 2018: An attempt to find an out-of-court agreement between Mediaset and Vivendi through mediation fails, and the pay-TV battle continues in court.
** MARCH 2018: Activist hedge fund Elliott takes a stake in TIM and launches a campaign to shake-up the way Vivendi has been running the company. The fund becomes TIM's second-largest investor with a 9 percent stake.
A planned joint venture between TIM and Vivendi's pay-TV unit Canal+ is put on hold after opposition from some TIM board directors. TIM says will pursue content partnerships on a standalone basis
** APRIL 2018: Mediaset signs a content deal with Sky's Italian unit as part of efforts to reshape its struggling pay-TV business, making a settlement between Vivendi and the Italian broadcaster look less likely.
Italian state lender CDP buys a stake of close to 5 percent in TIM to safeguard Rome's interests.
** MAY 2018: Elliott pulls off a boardroom coup at TIM, wresting control from Vivendi. The U.S. hedge fund secures two thirds of the available seats on TIM's board after a shareholder vote, while Vivendi's slate gets the remaining five. Vivendi insists it remains committed to TIM for the long term.
TIM and Mediaset sign a content agreement, in a move that further isolates Vivendi.
TIM says Vivendi no longer exercises control and coordination over the company.
($1 = 0.8463 euros) (Reporting by Agnieszka Flak; Editing by Mark Potter)