Transfer of Mosshouse - but who held it?

[William Douglas]

Grant by way of transfer of mortgage by King James I to John of St Michael (Johann de Sanctomichaele) scutifer of rights in lands of Mosshouses (Moshous, Moshouse, Mosehous) within the barony of Melville (Malewing) within sherrifdom of Edinburgh which had been surrendered to king by reason of mortgage by Henry Douglas of Lugton (Henry de douglas de lugtoune), to be held by John St Michael for £100. Dated under privy seal at Edinburgh 13 September 24 James I [1429], witnesses: Reverend Father in Christ John our Chancellor and George Bishop of the churches of Glasgow and Argyll (Argadien'); William Earl of Orkney, Master William de Foulis custodian of our privy seal, Master Thomas de Merton or Myrton (miretoune) dean of the church of Glasgow and divers others.

Henry Douglas of Lugton was being held hostage following the release of King James I as surety for his bail for the payment of the 60,000-mark ransom.  But James did not have the funds to pay this ransom, and Henry being held, he was able to remove from him Mosshouses and sell the lease to John St Michael.

Who this Henry was is a bit of a mystery.  We know that a Henry Douglas of Lugton was the progenitor of the Douglas family of Lochleven and ultimately the Earl of Morton.  But this Henry was dead by 1429.  He supposedly had an illegitimate son, also Henry - but would be be 'of Lugton'?

It seems possible that a natural son might have been given Mosshouses, so that seems a possibility.  But there was also a grandson, Henry, who also might have been the inheritor.

So - this is where I am:

The most probable scenario historians deduce is that the legitimate grandson, Henry, was the one held hostage, but that the King's action in 1429 involved the land (Mosshouse) originally granted to the natural son, Henry.

The natural son (Henry) likely died sometime between 1392 and 1429, allowing the Mosshouse property to revert to the main family line (now held by Henry the legitimate heir/hostage), who then lost it due to the mortgage being forfeited while he was in England.

In short: The hostage who survived and inherited Lochleven was the legitimate son, but he suffered a financial loss involving property originally tied to his natural half-brother.

What do you think?

Note: This charter is held by St Andrews University.