US firms Mayer Brown & Platt and Hogan & Hartson's London offices advised on eastern Europe's biggest M&A transaction.
London counsel Rob Lyons led the Mayer Brown team advising Deutsche Telekom on its $2bn (£1.25bn) acquisition of central European and Russian mobile telephone assets from MediaOne International.
He was assisted by corporate partner Mark Nicolaides, who works in the firm's Cologne office, and Mayer Brown London-based associates Kimberley Heimert and Steven Milne.
Deutsche Telekom bought Westel in Hungary, Russian mobile phone company RTDC and Poland's ERA.
The deal saw Clifford Chance acting as local counsel on the opposite side from its merger partner Punder Volhard Weber & Axster. Clifford Chance advised MediaOne in Poland while Punders acted for Deutsche Telekom in Russia.
Nicolaides says: "It was a pretty straightforward transaction, but it was the largest acquisition in central and eastern Europe to date.
"It underscores the dramatic increase in mobile telephone values over the last four or five years.
"These increases have been further demonstrated by the sale of Orange to Mannesman.
"It shows these full volumes exist in eastern Europe as well as in the member states of the European Union."
Hogan & Hartson's corporate partners in London Ray Batla and Michael Proett led the team as lead counsel for MediaOne.
Hogan & Hartson also acted for MediaOne in Hungary and Russia.
Allen & Overy advised Deutsche Telekom in Poland, with local firm Gardos Benke Mosonyi Tomori acting for the German communications group in Hungary.