This is a fairly rough TL based on the POD of Harald Hardrada remaining in Byzantine service. I've got an outline of events up to 1080 or so, but for now here's the first six years:
1042 ad:
Harald Hardrada, exiled prince of Norway
and hero of Byzantium's wars in Sicily, petitions
the newly crowned Emperor Constantine IX for
release from Imperial service. Constantine declines
Hardrada's request, instead offering him promotion
to the rank of Protospatharios. This offer, along
with the sizable bribe Varangians traditionally
recieved from new Emperors (known as the polutasvarf)
was sufficient to convince Harald to remain.
1043 ad:
Harald serves as Ethnarches (commander of
foreign mercenaries) in the Imperial army sent to
crush the rebel forces of George Maniakes, the ousted
Exarch of Italy. Harald's troops serve in the front
line at the Battle of Thessalonika, where Maniakes is
slain.
1044 ad:
Hardrada marries Ellisif, daughter of Grand Prince
Yaroslav of the Rus in Constantinople.
The two had been betrothed since Harald's service in
Kiev, but Yaroslav himself had awaited proof of
Harald's valour before condoning the engagement.
1045 ad:
Byzantine forces annex the Armenian Kingdom of Ani,
giving them a shared frontier with the Sejuk Turks
for the first time.
In Constantinople Ellisif bears Harald a son, but the
child is stillborn.
1046 ad:
Emperor Constantine agrees a formal peace treaty with
Yaroslav of the Rus, putting an end to intermittant
raiding from Kiev. Constantine's daughter Anastasia
is wed to Yaroslav's son Vsevolod.
1047 ad:
Hardrada and the Varangians serve in the defence of
Constantinople against the rebel army of the
Emperor's nephew Leo Tornikios, protecting the
Emperor as he personally lead the defence. Leo is
captured during the battle, and his forces disband.
In Norway, Harald's nephew Magnus drowns whilst
leading a fleet to engage King Sweyn II of Denmark.
The Norwegians, absent a clear heir, descend into
infighting whilst Sweyn prepares for a counter-attack.
1048 ad:
Harald acts as Protostrator (second in command) of
forces combating the depradations of the Pechengs
into the Balkans.
Byzantine forces clash with the Sejuks for the first
time, resulting in an uneasy truce.
Sweyn launches his invasion of Norway, taking most
of the South with little resistance. His forces are
intercepted outside of Trondhjem by an alliance of
Jarls led by Magnus's son-in-law Håkon Ivarsson.
The Danes are victorious and take the capital, but
take too many losses to continue to push north.
1042 ad:
Harald Hardrada, exiled prince of Norway
and hero of Byzantium's wars in Sicily, petitions
the newly crowned Emperor Constantine IX for
release from Imperial service. Constantine declines
Hardrada's request, instead offering him promotion
to the rank of Protospatharios. This offer, along
with the sizable bribe Varangians traditionally
recieved from new Emperors (known as the polutasvarf)
was sufficient to convince Harald to remain.
1043 ad:
Harald serves as Ethnarches (commander of
foreign mercenaries) in the Imperial army sent to
crush the rebel forces of George Maniakes, the ousted
Exarch of Italy. Harald's troops serve in the front
line at the Battle of Thessalonika, where Maniakes is
slain.
1044 ad:
Hardrada marries Ellisif, daughter of Grand Prince
Yaroslav of the Rus in Constantinople.
The two had been betrothed since Harald's service in
Kiev, but Yaroslav himself had awaited proof of
Harald's valour before condoning the engagement.
1045 ad:
Byzantine forces annex the Armenian Kingdom of Ani,
giving them a shared frontier with the Sejuk Turks
for the first time.
In Constantinople Ellisif bears Harald a son, but the
child is stillborn.
1046 ad:
Emperor Constantine agrees a formal peace treaty with
Yaroslav of the Rus, putting an end to intermittant
raiding from Kiev. Constantine's daughter Anastasia
is wed to Yaroslav's son Vsevolod.
1047 ad:
Hardrada and the Varangians serve in the defence of
Constantinople against the rebel army of the
Emperor's nephew Leo Tornikios, protecting the
Emperor as he personally lead the defence. Leo is
captured during the battle, and his forces disband.
In Norway, Harald's nephew Magnus drowns whilst
leading a fleet to engage King Sweyn II of Denmark.
The Norwegians, absent a clear heir, descend into
infighting whilst Sweyn prepares for a counter-attack.
1048 ad:
Harald acts as Protostrator (second in command) of
forces combating the depradations of the Pechengs
into the Balkans.
Byzantine forces clash with the Sejuks for the first
time, resulting in an uneasy truce.
Sweyn launches his invasion of Norway, taking most
of the South with little resistance. His forces are
intercepted outside of Trondhjem by an alliance of
Jarls led by Magnus's son-in-law Håkon Ivarsson.
The Danes are victorious and take the capital, but
take too many losses to continue to push north.