
In January 2005 Matthaios won the British Arts Foundation Fellowship Award 2005 as the best UK performer-instrumentalist, working in a non-western musical tradition. He has performed the Pontic lyra at WOMAD music festival in Reading (England 2001 and 2005), WOMEX music festival in Rotterdam (Holland 2001), Roskilder Rock festival (Denmark 2002), Teatro Massimo for UNESCO (Palermo Opera House, Italy 2002), Royal Albert Hall (in a Charity concert for the children of Afghanistan, London 2002) and at the Royal Festival Hall at London's Southbank Arts Centre. He performed the Pontic lyra for BBC Radio 3, as well as in many other BBC radio programmes.
In August 2004, he also performed the main music theme of the BBC television for the coverage of the Olympic Games of Athens with the opera band Amici and Prague Symphony Orchestra. In the same year, Matthaios collaborated with Ostad Ardeshir Kamkar on the Persian kamancheh in Tehran. In May 2005, he performed at Herodus Atticus Theatre in Acropolis, Athens, accompanied by ERT Contemporary Symphony Orchestra for the opening ceremony of the Athens Festival.
In 2006, Matthaios was the co-artistic director for the opening ceremony of the International Byzantine Congress of London with Lady Marina Marks as Chairman and HRH The Prince Charles as Patron. In March 2007 he performed at the Porchester Hall (Bayswater, London) with Cat Stevens (Yusuf Islam). In March 2008, he performed the Pontic lyra as a solo artist at the Royal Albert Hall for a charity concert organised by the Islamic Relief UK. In September 2008 he was a soloist with the ERT orchestra of contemporary music at Thessaloniki's song festival context. In November 25th 2008 he performed on the Pontic well-known Hollywood melodies accompanied by Ukraine Symphony Orchestra at Victoria Hall, Geneva. His appearance as a solo artist at the Art Palace Centre of Suleimaniye in Iraq (16-2-09), makes him the first Greek musician to visit and perform in Iraq ever.
Matthaios has shown a great interest in the stringed family of musical instruments; he plays instruments such as the violin, laghouto (Greek lute), oud, bouzouki, guitar, Persian kamancheh, Afghan rubab, as well as the Afghan and the Uzbek ghichaks. Having participated in many music concerts and recordings, Matthaios has managed to put forward a personal statement over the musical tradition he embraces and to which he has devoted his life.

