Not everyone can boast that they are related to a former Prime Minister, or to one of Shakespeare's alleged lovers. But Dan Snow can do both.

The young TV historian already has an accomplished close family - his father is broadcaster and co-presenter Peter, whose cousin Jon is the Channel 4 News anchor - but it seems his ancestors were even more distinguished.

"David Lloyd George is my great great grandfather and we're all very proud of him," says Dan.

"He was Britain's first working class Prime Minister and is definitely up against Churchill for the greatest one.

"He had a pretty impressive record really, coming in back in 1916 when we had the worst years in British history. We were in danger of losing the Battle of the Atlantic, we'd had a hideous loss of life on the Western Front and David Lloyd George came in and provided charismatic leadership that helped Britain win the war."

David Lloyd George is also famous for being Britain's first Welsh Prime Minister, but curiously Dan is related to him through his Canadian mother, Ann MacMillan.

"He's my mum's mum's mum's dad!" explains Dan. "My great grandmother was Welsh-speaking and lived in North Wales, then my grandmother emigrated to Canada."

It is apt that Dan's great great grandfather should have had such an impact on the course of World War I, since Dan and his father Peter have carved out a niche as the foremost military historians on TV - with BBC series including Battlefield Britain and most recently 20th Century Battlefields.

But the 29-year-old says he is just as proud of his relatives who actually fought in World War I.

"My great grandfather fought at Gallipoli and was almost killed there and my other Canadian great grandfather fought in the trenches at Ypres. We're not snobs in my family. We remember everyone!"

Dan's love and knowledge of history (he got a First in Modern History at Oxford) stems from the stories his family used to tell him as a child, he says.

"I just thought that's what people did, you talked about your grandparents, your grandpa told you stories about the war, so I never had a problem not enjoying history because it was so natural," he says.

But when the team behind the BBC family history hit Who Do You Think You Are? offered to search his family's past, he was surprised by the results.

"It turns out that we're descended from the Earl of Southampton, who was allegedly Shakespeare's patron - Shakespeare had the idea of writing Romeo & Juliet in the Earl's garden and he was arguably Shakespeare's lover as well! Some experts think he appears in the sonnets as well, so I am descended from a man who was Shakespeare's lover, possibly... That's very cool!"

But that wasn't all. Dan continues: "They went back even further to the early 1300s and - goodness knows if it's true or not - we're also supposed to be related to Roger Mortimer. Edward II was a very bad, very unpopular king and Roger Mortimer stole his wife, killed Edward II and ruled in his place until Edward II's son Edward III got rid of him.

"I was very proud of him as well, because he's a bit of a legend. He's also one of the only men who's ever escaped from the Tower Of London."

Dan comes from a long line of military men - in fact, he admits: "I'm actually the first man in my family in four generations not to be in the army".

TWO WAYS TO FIND OUT MORESearch military recordsLike Dan, most people will have ancestors who, at some point in their lives, have seen action in the armed forces.

As part of your ongoing family history search, you will find that military records can be a very important source of information.

Did your forebears fight in some of the biggest battles of the First World War, were they ever held captive, and what medals were they awarded for their service?

You might be lucky enough to find letters, documents and even medals tucked away in the attic that could answer some of these questions, but another good place to start is talking to surviving relatives.

"That's my first piece of advice," says Dan. "Lots of people have never really asked their grandparents and I think you should because there's not many of them left now. "They might not want to talk about it but perhaps they do. It's amazing how few people ask, so I firmly recommend that they do and I urge them to do so before people pass away."

Once you have found out what you can from relatives, you will need to begin searching records - and the easiest place is online.

The National Archive (www.nationalarchives.gov.uk) holds all the public records for England, Wales and some Irish records, while Scottish records can be found at The National Archives Scotland (www.nas.gov.uk).

Dan recommends starting with records from the First and Second World Wars, because most of the country was involved The National Archives' website features a section dedicated to researching military history and you'll also find tips on how to get the most out of your research, or a visit to the archives.

These include making sure you know the full name of the individual you are searching for and knowing which force they served in (army, navy, airforce or marines) as well as the regiment, battalion or ship. The date when your ancestor enlisted or was demobilised is also useful.

Campaign medals from the First World War are one of the most frequently searched documents, and there are also combat reports, airwomen's records and obscure records relating to defence policy, espionage, even propaganda.

Further records will be found at the Commonwealth War Graves Commission. Try the Ministry of Defence website too, to find your ancestor's regiment (www.mod.uk).

Local newspapers published lists of casualties between 1914 and 1918 too and are worth exploring.

Key campaignsTo get more of a flavour of the conditions that your ancestors endured while in service, use the war records to find out which campaigns they might have been involved in during World War I.

If, like Dan, you know your great great grandfather fought at the third Battle of Ypres (also known as Passchendaele) on the Western Front in 1917, a visit to the site could be a rewarding experience.

"My great grand father Dr Robert MacMillan was a Canadian who'd signed up to join the British army because he felt that was the right thing to do, to join with the old country, and he fought on the Western Front," says Dan.

"Robert had fought at Ypres and I have been there - it was very moving to think he was there."

Dan and his father Peter examined some of the most dramatic battles of the 20th century in their most recent TV series, which has now been turned into a book.

The descriptions, including that of the Battle of Amiens in 1918, give an insight into conditions in the trenches and the spirit which kept your ancestors fighting.

"They're the most extreme conditions any human can ever live under. You'll develop friendships that are stronger than any friendships in civilian life, you feel love, fear, pity, hatred, courage. It's absolutely fascinating," says Dan.

Websites such as www.firstworldwar.com will give you in-depth descriptions of all the major battles during World War I.

Some battlefields have dedicated war museums, while the Imperial War Museum in London, the National Maritime Museum in Greenwich and the RAF Museum at Hendon will also prove vital.