By David Willey
BBC News, Rome
The London Stock Exchange (LSE) is to buy its Italian equivalent, Milan's Borsa Italiana, for more than 1.5bn euros (£1.1bn; $2bn).
The new board will have seven British and five Italian members
The deal done on Friday was confirmed in a joint statement by the LSE and the Borsa Italiana.
Shareholders in the Milan stock exchange will be offered just under five shares of the LSE for each ordinary share in Borsa Italiana.
The new board will have seven British members and five Italians.
The merger was welcomed by the Bank of Italy and by Italian business and political leaders who described it as very beneficial for Italy.
The governor of the Bank of Italy, Mario Draghi, said it would bring the Italian stock market out of its present isolation. The Borsa Italiana was privatised by Mr Draghi 10 years ago.
A former president of the Borsa, Stefano Preda, said the merger would put an end to the marginalisation of Italian business and make international capital more accessible to Italian entrepreneurs.
The deal has still to be confirmed by shareholders but if it goes ahead it will strengthen confidence in Italian business in European markets.
Global stock exchanges have been seeking partners in recent years, in a bid to cut costs and increase business.
This deal comes just over a month after the completion of the New York Stock Exchange's takeover of Euronext, which controls the stock markets of Paris, Amsterdam, Brussels and Lisbon.