David Williams Political Editor BBC Wales

BBC News Online completes its series profiling the leaders of the four main political parties in Wales

A heavy iron plaque rests against the back of the desk in Ieuan Wyn Jones' study at his home in Anglesey.

It is a solid reminder of his first calling - the law.

"Most families have experienced some sort of scandal - it is part of the rich tapestry of life. Ieuan Wyn Jones

Engraved on the plaque is a picture of a cow with two farmers - how shall we put this delicately? - furiously pulling at either end.

In the middle, alongside the udder, a figure is seen milking the poor creature.

The figure depicts a member of the legal profession who is clearly enjoying the benefits of the dispute between the two farmers.

The plaque was given to Ieuan Wyn Jones when he gave up being a solicitor to pursue another and arguably less lucrative career in politics.

That was almost 25 years ago.

Family Man: Mr Jones researches his ancestors

Now, he is the leader and president of his party, Plaid Cymru - the Party of Wales.

There are still occasional opportunities to milk difficult situations, but in the main it is a much tougher life of endless disputes with political opponents and, occasionally, members of his own party.

To escape the constant demands on his time, Ieuan Wyn Jones indulges in what has become a labour of love - tracing his family tree.

Surrounding the plaque and littering his desk are old birth certificates, faded black and white photographs of his most recent ancestors and a picture of the family farm in the last century.

"I think it is very important for a politician to have wide and varied interests, otherwise living in the goldfish bowl of politics you can become a pretty one dimensional person," he tells me.

Opinion poll: A family diary talks of the 1906 election

In an effort add another dimension to his own life, Mr Jones trawls through the family archives which paint a vivid picture of life on Anglesey in the second half of the 19th Century.

He is particularly blessed in his meandering through times past in having the diaries of his great aunt, Mary Williams

The diaries, mostly written in Welsh, paint a fascinating picture of life in the late 19th and early 20th Century and there is just the hint of scandal as well.

It seems that couples marrying in this period often left the island and crossed the Menai Strait for a ceremony in Caernarfon.

It was a day out for the whole family, but it seems that one member of the family went much further and trekked - and it was a trek then - to Liverpool for her celebrations.

'Jigsaw'

The question is, WHY?

Ieuan Wyn Jones hints at a skeleton falling out of the cupboard here, but he is much more concerned to discover what happened to another member of the family who was lost at sea.

"That is a missing part of the jigsaw," he says.

And adds: "Most families have experienced some sort of scandal. It is part of the rich tapestry of life.

"When you are trying to piece together the family jigsaw, a missing piece only makes you want to carry on."

He is finding it harder to find time for his personal jigsaw as politics increasingly takes over his life.

History's heritage: Photos of the Jones' clan

"It's now a 24-hour-a-day commitment, " he says. "For that reason it is even more important that you have time out to do other things.

"It gives me immense pleasure to research something other than politics."

There are occasions when the two things - researching the family tree and politics - converge.

He was particularly interested in another diary entry from 1906.

Aunt Mary noted that it was the year when, for the first time, the Tories were wiped out in Wales.

She could not possibly have known that the family member reading the entry a century later would soon be engaged in an important election of his own.

Secret

In May this year, Ieuan Wyn Jones will be attempting to consolidate his own position and lead his party to further electoral success in the Assembly elections.

What would his great aunt have made of that?

By way of reply, Mr Jones let us into a little secret of his own.

He too has been keeping a diary, but it will be sometime before we discover whether there are any political skeletons or scandals lurking in that particular cupboard.

"I'm not prepared to release any information from that (diary) for years to come, " he says.

For the time being, then, another piece of the Jones jigsaw is missing.